I'm 31. Was introduced to D&D at a fairly young age but didn't have much interaction with it outside reading my brother's books, occasionally watching them play, and of course the computer games (Eye of Beholder and eventually Baldur's Gate). Played a few games in AOL chat rooms back when that was a thing people actually did. Didn't really get involved in table play until I hit college (2003) with Star Wars D20, Hackmaster and eventually D&D 3.5. Don't think I joined the forums here until 4e hit the shelves.
But then, I've been posting in forums, in one form or another, for at least the past 20 years. Other than moving from AOL to web browsers I can't say the functionality has improved much since. Never really understood the appeal of Reddit; it just always struck me as a forum with worse functionality and little-to-no moderation.