I have had people telling me since I was 17 that they were going to get me wasted/wait til I was wasted or asleep then cut my hair. I have lost count of the number of people who have said I should get a haircut.
End result: I'm now 33, I still have long hair and I work among short haired yuppie bastards in St Kilda Road and I know some people are like, what the hell is he doing working here?
Fuck 'em all, that's what I say!
If you want to cut it, do it, if you don't really then don't do it to please narrow minded dumbarses!