Ah the decisions of youth! I remember people saying "if you have long hair you will get nits" (they actually prefer short hair). "Why should we have to wear a uniform, teachers don't" (that was a really dumb one).
When I was at school I had the old "short back and sides" at the time (60's and 70's). I guess if you can have what you want when you are young, there is nothing to aspire to when you get older, leave school, get a job...a mortgage...etc.
My hair at the moment is the longest it has ever been (over the collar) and still growing (after 12 months, such hard work). I have been asked by a number of people why I am growing it, and I usually say to them "because I can" (not so much to do with "allowed" as having something to grow). Being a programmer, I think you need to grow a pony tail at some time in your life! I guess I had three alternatives: the blonde bimbo (my wife wouldn't appreciate that), the red sports car (my wife would insist on driving it) or long hair (she the one that suggested it) so being an idependent person, I did the one that would cost the least
As regards your hair, you could fight if you want, but you probably won't win..."compromise is the art of good business" (heard this recently from a guy with shocking hair
) so maybe try compromise...I think they would go more psycho if you shaved it all off, but don't forget the sun block