Ummm...your parents will probably kill me if they read this, but here goes...I'm a 37 year old mom of three (one is a 16 year old boy) and whatever he wants to do to his hair I AM FINE WITH!!!! I read a story once somewhere where this dad hassles his son about his hair all the time-even though the son was a great student, good person, etc... One day, while the dad was at a basketball game that his son was playing in, the son dies (apparently he had an undiagnosed heart problem). The dad then, too late, realizes that IT'S ONLY HAIR! That story hit home with me and it is the truth. If my kid is a good person, and the only thing he does "wrong" is chooses to do nutty things with his hair, then I'm a lucky mom.
BTW...I am also a preschool teacher, and I dye my hair all the time. I'm going light blonde tonight (from a reddish color that keeps on happening b/c I'm letting my husband-yeah, my husband-dye my hair). I also cut my hair different ways all the time. It's just a mode of expression, and I think your parents need to chill.
I know your comment is over a year old, but I wanted to say that this right here is exactly what my parents felt when I was growing up. I was a pretty good kid and I just liked dying and cutting my hair a lot (well, I didn't actually cut my own hair until recently, but I dyed it a lot, mostly out-of-the-box and by myself.) And my parents used to tell me basically what Miss Barbara said... If I was a good kid and all I wanted to do was go a little crazy with my hair, that they were so lucky. It always made me feel good.