Also, there are groups. The biggest one is @bookstodon but simply typing @ bookstodon will not get you there. You need the full address which is @ [email protected]. (I put a space after @ just to show you the non-shortened address, which will become a shortcut link after you hit send.)
This page can help you find groups, and there is one about autism which might interest you: https://a.gup.pe/