If you hold the opinions of teenagers or college students in high regard (and you shouldn't) they pretty much think you die at 30, so of course they think it's old. Like that club joke in the OP... as if that's what matters most in life, rather you can still club with 21yos.
If that sounds like salt, well yeah. Nobody wants to "get older" once you hit your peak. But it'll happen to them to, so let them have their fun before it's gone. I wish all people would enjoy it while it lasts. A day will come when you look around and can't believe you're already "old" and it's gonna suck, but you'll get through it. The real kicker is we all hear things like this told to us by olds all our lives, but we really don't stop and think that it WILL REALY happen -- but it does and will. It feels like it's an eternity away, but once it arrives you won't think that at all, you'll think, wow, already?
For myself, I feel older but not old. Mind over matter.