Mid-twenties. Young enough to still "know" what all these young folks are talking about, slightly old enough to have learned to pay little attention to it.
You'd be amazed, absolutely amazed at the things you find yourself not caring about once you leave high-school. Being in a high-school environment traps you in a mindset in which little differences mean the world and relatively unimportant things matter to you. Let me tell you - once you get a job, once you've gone to university and hopefully got a bit more knowledge under your belt, suddenly "who likes who" and "what band is hot" and "what gang I hang around with" ceases, absolutely CEASES to matter. Well, at least, it SHOULD cease to matter to you..