When you were younger than 18 did you play any 18 rated games?
Did you watch any 18 rated movies?
Listen to any music or read any books aimed at adults?
Read any porno mags or watched a porno?
If the answer is yes and you agree with the OP then STFU. you're being gits, just because you're older now and you're allowed to consume such content does mean you can suddenly be a diak to people younger than you.
If the answer is no then either you're lying or you had a crap childhood.