17 - and I'd like to note that this is one of the few forums on which I can have that information public and still be able to participate in (mostly) civil public discourse, without put-downs, pats-on-the-head, or pandering. It's a breath of fresh air.
Only kidding, maturity varies wildly in online communities, I think age is very often not correlated.
Oftentimes I think that kind of patronising can be the result of jealousy. You know, youth is something you come to miss more than you think you would (31 here...)