I don’t know whether you’re autistic. For that matter I’m not diagnosed either, I’m just basing this off of my being very much like my daughter. I’m somewhat different than you (I enjoy reading and writing fiction too, but on the other hand I can do the dance and fake whatever I need to). But what I will say is that I know more than one autistic girl/woman who is very much like you. Socially aware? Check. Can’t fake? Check. Reading and writing rather than math? Check. Various stimulation issues? Check.
One thing though. It seems to me, in my opinion as a random person on the internet (so take that for what it’s worth), that you’re in that murky Venn diagram of ASD/profound-giftedness/ADHD where it’s not really clear where one shades into another. To be honest, that’s where I am too, only I’m a little further to the ASD side and a little farther away from the ADHD side than you. (I have a few ADHD tendencies too – really very few compared to those who actually have the diagnosis, but I do have them – and ADHD strategies often help me (though not always).) I don’t think that it’s really well understood why there’s such an overlap, but there’s definitely a big overlap and I know a lot of 2E (3E?) folks who are in various places on that diagram.
(Btw, my ASD kid also craves novelty, though she’s not ADHD at all. It was really hard when she was little and I’d take her to do an activity and she’d spend a few minutes with it and be like, “OK, what’s the next thing?” Now some of the benefits are more clear – like, some autistic kids hate trying new foods, but she loves trying new foods.)
(And I also wanted to say, like @liirogue , that I’m sorry this has all been and continues to be so hard for you. I’m sorry you didn’t get the mom you ought to have had, while I think it’s wonderful that you can be that mom for your own child.)