What are the down-sides to a haircut?

There is this haircut seminar thing at our school call St. Brodericks. At first I thought it was only for boys and they do it for fun. But, I also saw 4 or 5 female students getting thier head shaved too.

Now this thing only happens once a year at school, so of course I have to wait until next year. But, I was thinking of doing it too. I have not asked my mother about it yet, and my friends say it might take a while to think about. The girls who got thier hair cut looked great and I wanted to help the cause.

Any advice?