Wanting to get an assessment at 40

I am growing increasingly convinced over the last 3 years or so that I may have Aspergers.

it is becoming more and more apparent to me and I just want to know if i have it because it would be a massive relief and help me to explain to people why I am the way I am especially when it comes to sticking to a routine and socialising being a major source of anxiety.

i am really just fed up with being misunderstood I do not have depression but I do have social and general anxiety and also at health anxiety.

i have hypersensitive hearing and sense of smell and touch. 

‘I really feel it’s time to get assessed as pushing myself into being more social or into doing things does not in any way improve my aversion to wanting to be around lots of people I feel it means I have whole lot of acting to do and things to think of to talk about. 

How do I prepare for an appointment with my GP to discuss this? 

Is there somewhere where it lists what things to mention or examples? 

Also should I be prepared to be told I’m just overreacting or being silly? As this concerning me. 

Many thanks for your time in reading