What positive steps did you take after (adult) diagnosis?

The diagnosis gave me a sense of relief.  I now don't 'beat myself up' for being odd & different.  I know there's a reason for it.

But even before diagnosis, I'd started to adapt - the Noise Cancelling phone headset at work is wonderful for cutting out office chatter!

I did tell colleagues - very helpful to be finally able to explain that not making polite conversation during a phone call was not me being rude, but functioning well and working hard.

Thanks to everyone who replied.  Had what should have been the final assessment last Friday, but we didn't get through all the questions so I need to go back again in September to complete it, either with the same worker or with the psychologist (though I was told not to read too much in to which one it was).  I thought it went quite well, felt quite relaxed during the questions, and managed to answer most of them.  Will update once I know more but really appreciate others taking the time to let me know their experience.  This has helped me put things in perspective, and made me less nervous about the after-diagnosis (or not!) period

You put into words exactly what my son has tried to tell me on a number of occasions, "There are so many talentless, lazy individuals who have done so much better than I have and are so much better-liked. It makes me so frustrated sometimes because nobody has ever given me a fair chance or the benefit of the doubt, and it can only be because I am socially different." This is exactly how he feels. 

Did Diagnosis help?

I suppose that depends on what you mean in terms of 'help'. Through that label, it helped me gain access to support I needed at that point in my life. To put it into context, I was diagnosed at 32. Sure, childhood was tough, I had my issues, but obviously there was a lack of understanding and awareness combined with the fact that my parents were also having their own problems to deal with. I was just seen as shy and having developmental problems. Growing up, I struggled, didn't fit in, was obviously different and I probably wasn't fully able to understand everything I was going through in my earlier years. School was a terrible experience in lots of ways but I focused on getting an education under the assumption that as long as I worked hard and got results I could move on from that place, leave all the people behind that made my life hell, and finally get on with life away from them. Of course I understood I was different and spent a lot of time trying to work out how to fit in, clearly it was never going to happen, and I never did fit in. I came to accept the fact that I was different and didn't fit in. I went off to university, which was also a struggle in lots of ways but I pushed myself to be able to get on with things. However, I struggled with a group project and couldn't actually deal with the group. I left university to give myself a bit of time and space to think. I returned to university to do a different course, which I ended up getting a degree in. Even during this time, I was slowly taking some steps forward pushing myself, reflecting on my life, analysing myself, my thoughts, my feelings, my behaviours, etc. I came to all sorts of conclusions, so in a way university was the start of my journey as I left home and had to start facing the world and challenges on my own of which it wasn't an easy experience, but looking back on all of this it demonstrates both my resolve and determination to keep going no matter what. I started to find myself in a way though there was still one major issue, I could only view my life through the lens of building a career as everything outside of that was a problem I struggled with. However, I could demonstrate my ability to work and get on with it to a high degree. People and every day life was a far bigger challenge, which is why I focused on work, I could become successful by working hard and moving up in my career as it was the only value I could see in my life. The only thing I seemed to do well at was working hard. I came out of university and got a job in the real world, which was where life took a turn for the worse in a way. The problem I had was a naïve assumption that working hard, ability, etc. would be recognised and valued. I didn't go to work to make friends, I went to work to do my job to the best of my ability. Unfortunately, work presented many challenges with discrimination and abuse in various forms (this was before I was diagnosed). I kept pushing through it, every challenge made me push myself harder, every obstacle made me determined to find a way around it. However, the one issue that could never be dealt with was the wall created around me by the people I worked with who isolated me, excluded me, treated me like dirt, etc. I learnt a lot about the workplace and people in the corporate environment. By the time I was diagnosed I had already had practically everything taken from me in the workplace, they prevented me from gaining skills, knowledge, experience, they kept opportunities away from me, they made sure everything was always against me though I could only assume that for whatever reason they didn't like me even though I was working hard and at times doing a far better job than the management. Maybe I was just seen as a threat that needed to be dealt with. After my diagnosis, I had already been through a long journey of life through reflecting on my experiences, accepting that I was different, analysing myself and taking steps to deal with anxiety. It didn't really have an impact upon me because I knew I was different and had reached a point where I was ok with it. Shortly after my diagnosis, which I will admit I didn't report to work, because I was already fully aware of where I stood in the eyes of management and knew it would make no difference. No matter what supposed legal processes there are in place there is no protection from those who can find ways around the systems, processes and rules to deal with you. That was the type of people they were where I worked. I finally accepted that I was getting nowhere in building a career, competition was tough, I was lacking in skills, knowledge, experience, etc. because I was prevented from gaining any. I was more qualified than some of the managers through undertaking professional exams, which I got no help with. It was made clear to me through what was going on that I was not wanted there, except to simply do as I was told by the management as I was kept where they wanted me kept, so I ended up walking out fully aware that I had no idea what may happen next. They didn't think I would and I got support from my family for the decision I took. I had to sell my flat and move back in with family, which hasn't been easy to deal with. Now, as I said about the help I would need at a point in my life, my diagnosis helped give me access to some services that helped me get my next job, although only part time and minimum wage but I have found a job I enjoy working with people who are understanding and supportive, who recognise my value and acknowledge the hard work I put into the job. They say they would like to do more for me but they are a small organisation with limited resources and mainly run by volunteers. As for everything else, my life, my experiences, my self reflection, my analysing myself, etc. all brought me to a point where my diagnosis had counted for very little at 32 because the most difficult years of my struggles and my journey had been before then and I had come to accept myself for who I was as an individual.

Did things start to make sense?

In a way. It was only through my nephew getting a diagnosis as a child that my sister picked up on the symptoms/behaviours and made me aware of it. I wasn't aware of it until then, which shows that there's still a lot of work to do on increasing awareness. My sister then helped push for a diagnosis, which was done privately with funding provided from family. It helped explain a few things but as I've already said, by the time I was diagnosed, it didn't have the greatest impact on me. It just helped fill in some of the detail.

Did you do things differently as you were more aware?

No, because again, the diagnosis had little impact on me. I had already come to terms with my differences and didn't really care what others thought any more. I had given up on the idea of fitting in and belonging when all I needed to do was be myself and it was a problem for others if they couldn't accept me.

As for telling work colleagues, you'll more than likely know if it's right to tell them. There were some colleagues I could and did tell but as I already knew the situation with management I saw no point in telling anyone else as it wouldn't have changed anything. By that point I was already making plans to leave anyway, even if it meant leaving without another job to go to. If you had been there you'd understand. Now, like I say to others, life is tough especially the transition from education to the real world of work but if there's one thing that helped prepare me for the workplace it was the years of bullying and abuse I grew up with. I was already used to it but I saw others have breakdowns from what was going on who were there one day and gone the next. The world still has a long way to go to change for the better.

I'm a bit of a borderline case; I was diagnosed on the cusp of adulthood, about 6 months before my 18th birthday (though autism had been mentioned as a possibility earlier they had not been able to pin down a formal diagnosis due to my A. being female and B. masking competently). 

Did diagnosis help? 

Yes.
For starters, I was diagnosed in time for arrangements to be made to support me at university, without which I wouldn't have been able to complete the course.
At work I found my diagnosis provided extra protection when things did not go well (e.g. when I first started I had a personality clash situation with a colleague due to things directly attributable to my autism. My diagnosis meant I was treated more gently than I would have been and probably stopped any grievance sticking). 
Also, coming to terms with why I was different to people around me (and the fact that this wasn't something that would change or become easier with time) gave me the ability to make the decision to be more true to myself and stop desperately pretending to be neurotypical all the time, which in hindsight was something that was holding me back.
Also, as I am very open about being autistic, I find people are more accepting of my peculiarities and less likely to take long-term offence if I say or do something socially inappropriate or overly blunt.

Did things start to make sense?
Definitely. When I was first diagnosed I read this book http://www.autismforthvalley.co.uk/files/5314/4595/7798/Attwood-Tony-The-Complete-Guide-to-Aspergers-Syndrome.pdf and so much of it just clicked. It was a revelation. 
I was very aware for most of my life that I was different to my peers and completely socially inept. Until I had my diagnosis I just felt second-class in that regard.
Afterwards, I realised that I had been chasing the wrong goals to start with; I was never going to be Miss Always-says-the-right-thing. That took off so much of the pressure I had put on myself.
Also knowing there were people like me out there, not being alone in my difference, was something very special in itself. 

Did you do things differently as you were more aware?

Yes, I'm now much more likely to ask for accommodation where I need it. I'm much more true to myself in my behaviour; I've dropped the mask. And I'm much, much more confident and outgoing.
Due to my social difficulties, I kind of always assumed I was an introvert before I was diagnosed but I'm not and I never have been. I'm an extrovert with no idea what she's doing and the need for occasional rest breaks! XD
I didn't notice all these changes straight away. It took time and effort to change my approach to life, but the knowledge of my diagnosis certainly helped me to recognise that the way I had been (constantly pretending to be 'normal' and trying too hard to please socially) was not true to myself, not good for me psychologically and not sustainable.

Re. disclosing at work;
I would generally say to do so to your manager; if you do need help at some point (e.g. because something changes) it's harder for your employer to provide support if that's the first they hear about it. 
Bar that it's a personal decision but I am extremely open about it and have almost never encountered a negative response. If you treat it as a matter-of-fact thing people tend to copy you in that attitude, from my experience.
(Of course, my experience may not be the norm because I work in education, where my colleagues mostly have some degree of autism-awareness training and are sometimes just quite pleased for the opportunity to get an insider-view of their more challenging aspie students!)

I knew growing up that something was odd, but not what. Diagnosis did help, tremendously, providing context around so much of my life.

So yes, a lot of things started to make sense. Behavioural things, emotions, reactions, preferences.

I did do things differently. It made me far more aware of things that cause me problems, and how to avoid, mitigate or work through them. I changed my lifestyle a little, shifted my approach to work and became a much happier person.

One thing I didn't do is tell work colleagues. If their expectations and standards around communications and behaviour aren't being met, that's an opportunity to improve. That it takes me much more effort than them in some of those areas doesn't mean I shouldn't try. What I did do is let HR know, on a "You must not tell my boss" basis, so that if adverse reports came in I could highlight the underlying limitations that it would be lovely for them to help with. In the past I wish I'd had that; since diagnosis it interestingly hasn't been necessary.

I haven't become a god of communication, just much more conscious about how I do it, how people perceive me and how to fake the engagement they anticipate.

But.. you're planning ahead here. I approached my GP asking for an assessment for ADHD and it took 2-3 years to find out that it's Aspergers instead. The process takes time, it may deliver an outcome you're not expecting, so celebrate that you're making progress and focus on staying open to all possibilities.

First, I am still self-diagnosed as Asperger’s syndrome.

When I was attending a four year college, I was not able to finish this one test. I told the professor that I wasn’t able to finish the test when I turned it in. She told me I should find out if I qualify for my time.

I went through the process and the psychologist did figure out that I do have a processing deficiency. His results created an accommodation at the college I was attending. The additional testing time helped me tremendously because I got to showcase my test taking skills when it mattered most. I ended up graduating with my bachelors degree *** Laude.

 I do look back and realize 10 years of my life was wasted because I didn’t get that accommodation for my standardized test during my junior year of high school. I ended up studying the subject I wanted to study right of college too.

 I have received a lot of help for my Asperger’s syndrome. It hasn’t changed that I will obsess though. It hasn’t changed who I am.

As is the case with many on this site, I had self-diagnosed long before I was officially diagnosed. That was the point at which everything started to make sense. I didn't start to do things differently at that point, however, though perhaps my attitude was slightly different because I had just been through a really bad work situation.

The reason I got an official diagnosis was because of (yet another) problem at work, and now my life has completely changed (i.e. fallen apart). I think that's more to do with what happened at work (and the fact that it wasn't the first time it had happened) than with my diagnosis, but there is also something to be said for it being official and written down in black and white.

I often think about how different my life would have been if I had been diagnosed in childhood or early adulthood. I don't think it would necessarily have been better, because of the attitudes people have toward those they consider less "able". I would not have benefitted at all from intervention in school (which would perhaps have been forced on me), because I never had any problem achieving high grades and earning university degrees (I have several). The nightmare really started when I was finally in the "adult world" and people around me did unexpected things (such as behaving as though they were still in primary school) and I had no idea how to react.

I put a lot of effort and many years of my life into getting an education and building my career. I wish someone had told me before I started how much more difficult it would be for me than it for someone else. I naively thought talent and hard work were the keys to success, but that is a total lie. There are so many talentless, lazy individuals who have done so much better than I have and are so much better-liked. It makes me so frustrated sometimes because nobody has ever given me a fair chance or the benefit of the doubt, and it can only be because I am socially different.

I wouldn't tell all work colleagues, but it is wise to let HR or one's manager know in some recorded way, because otherwise, if something does go wrong. it will be more difficult to prove that the employer knew or should have known about the disability. I know this from personal experience. Everything always seems to be going well until it isn't. and then it's too late. You might want to specifically request discretion, because some managers are prone to letting everyone else know, even though they are not supposed to do so without your express permission.

That's just my experience. I hope it helps to put things into perspective.