Why couldn't I have just been made normal?

I 1000% understand and feel the exact same way. I was diagnosed about 5ish years ago now and I still hold a lot of anger inside that im not sure I'll ever get past. It's a lot easier said than done accepting something you despise knowing you can never be rid of it or change anything about it. I think being diagnosed as a adult comes with its own challenges aswell because as you said mental health comes into play massively and we know now these things probably could've been prevented or at the very least have had a lesser role should we have been diagnosed earlier in life. 

I was diagnosed late too (in my fifties) - my youngest child was diagnosed at about 10 years old and my youngest in his 20’s (they were both diagnosed before I was). I understand the feelings of anger and regret that things could have been different. But ultimately the past is gone, and it doesn’t serve us (or our families and loved ones) to keep holding on to anger and regret. If you can try to let go of emotions that are actually toxic to your life now. If you can try to focus on the advantages you do have. For example: can you walk around easily, do you have healthy hearing and eyesight? It’s easy to focus on all our problems and forget what we do have, the advantages we have that make our life better. Ultimately - with practice - we can encourage a happier mindset if we try to change our perspective on our situation. For example I had a dysfunctional childhood with parents who were critical and not affectionate and positive towards me, but I went on to meet my husband and have children and so have a loving family now. I could dwell on what I didn’t have growing up - but what good would that do? It’s better to focus on whatever positives we can. Sometimes if I’m struggling I’ll just go out for a walk and focus on the fact that I can see the blue sky and feel the sun on my face, and hear the birds singing. I try to ‘feed’ the feelings of gratitude and happiness rather than focus on the negatives. 

I was diagnosed late too (in my fifties) - my youngest child was diagnosed at about 10 years old and my youngest in his 20’s (they were both diagnosed before I was). I understand the feelings of anger and regret that things could have been different. But ultimately the past is gone, and it doesn’t serve us (or our families and loved ones) to keep holding on to anger and regret. If you can try to let go of emotions that are actually toxic to your life now. If you can try to focus on the advantages you do have. For example: can you walk around easily, do you have healthy hearing and eyesight? It’s easy to focus on all our problems and forget what we do have, the advantages we have that make our life better. Ultimately - with practice - we can encourage a happier mindset if we try to change our perspective on our situation. For example I had a dysfunctional childhood with parents who were critical and not affectionate and positive towards me, but I went on to meet my husband and have children and so have a loving family now. I could dwell on what I didn’t have growing up - but what good would that do? It’s better to focus on whatever positives we can. Sometimes if I’m struggling I’ll just go out for a walk and focus on the fact that I can see the blue sky and feel the sun on my face, and hear the birds singing. I try to ‘feed’ the feelings of gratitude and happiness rather than focus on the negatives.