I think the under 18 demographic has a couple of active representatives here on Wrong Planet. But maybe there are two factors you need to take into the equation.
Those of us who are over 18, say up to 25 or so, I've noticed often don't feel properly 'adult' yet... Now this is not too different from non-autistic people, but autism tends to be a factor that adds to the insecurities you'd already have as a young adult about how you're supposed to carry yourself in the adult world. And many WP posters in the 'early 20s' age range ask questions on the forum that are related to these issues.
Secondly, by now a lot of posters who originally registered when they were teenagers, are now over 18. They've moved from being the site 'babies' to being young adults. But joining the forum as a high school student, the circumstances under which you've found the forum and decided to register, differ ever so slightly from someone who's 22 and decides to join. Or someone who's 30. Or someone who's 52 and only recently diagnosed with Asperger's, and wants to find out more about it by joining WP.
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