@clacke in hindsight, all of the signs were there from a young age. I didn't speak until I was three, used to stim like crazy and have always had special interests. Plenty of other signs as well, but nobody connected the dots.
Part of me still occasionally wants to be upset with my parents for being clueless about it when I was a child, but I can't blame them really because I was so good at masking. As I've gotten older, I feel a lot less need to do so. I'm in a place I'm comfortable being me.