The first step is to stop thinking of your self as abnormal. If you are on the spectrum, then you're probably perfectly normal for somebody with an ASD.

I got diagnosed a year ago (at 27) and I'm glad I got diagnosed. I'd spent my entire life wondering why I never fitted in, why I seemed to react differently to most situations than my peers, why I felt I constantly had to explain that I preferred to be on my own than in a group, etc. A life time of thinking you're abnormal or weird does terrible things to your self esteem. I developed other mental health disorders including OCD and DID, along with continuous bouts of deep depression.

Sure, getting the diagnosis didn't fix the issues of my past, but it has given me hope that the future can be better now that I know I'm not abnormal or broken in some way, I'm just different and different isn't always a bad thing. If we were all the same then the world would be an incredibly boring place.

I'm not saying it's going to be easy, but at least I've got something to build on now.