Too Old?

Question: At what point am I too old to wear music/band related T-shirts?

I don't want to be a rule breaker.

UPDATE: Here is a chat transcription from this morning with my sister:

Gary R says: (11:01:34 AM)
   I'm conducting a survey:

Emily and CJ says: (11:01:49 AM)
   on me?

Gary R says: (11:01:55 AM)
   At what age am I too old to go around wearking concert/music related T-shirts.

Gary R says: (11:01:58 AM)
   yes.

Gary R says: (11:02:04 AM)
   everybody, more or less.

Emily and CJ says: (11:02:24 AM)
   hmm..when you are fat and smelly..stinky, too.

Gary R says: (11:02:37 AM)
   So about 14?

Emily and CJ says: (11:02:54 AM)
   let's just say, cj wore a stupid poison one until it was ruined..somewhere in his mid-twenties...

Emily and CJ says: (11:03:08 AM)
   so, as long as you have a cool band...and a nifty looking shirt.

Gary R says: (11:03:24 AM)
   I see.  I'll keep that in mind.