Probably in K-12? Like seriously everyone in my "friend" groups and half of my classes knew something about me was off, and I believe I was known as the eccentric genius throughout middle/high school (and my HS had a lot of smart students). But the broader culture I was in didn't believe in mental health so...
Other than that... there were two people I relate to very well on Mastodon (when I first joined), one of whom is very openly autistic; hence why I got tested. That's probably as obvious as it gets