Let me present myself: My name is Gustavo, 13 years old, and I'm from Brazil.
I have a very big problem in my home (as we're living one World War III here). This is because I want grow my hair and my perents says "NO 'CAUSE YOU'RE NOT EMANCIPATED!" and they threats me saying "I'll call two cops to arrest you and cut your hair" and THEY CAN DO IT due to some friends with badge and uniform. I retort saying "There's no legal argument to force someone to cut it's hair.". Sometimes they plan to put sedatives on my food/drink to cut my hair while I'm sleeping like a rock and it's easy because mama takes sedatives.
So, what do I do now? I hate to discuss about my hair every day.
BUT, there are some good news too: I am at one month without going to the barber shop, my hair is growing fast, nice and strong and I'm resisting peacefully (thanks God).
Dang that sounds like abuse!
I hope they don't carry out their threats :(
Birdman
Try asking them why they don't like you having long hair. Chances are they wont be able to think something up on the spot, and will give you an answer when they twist some sentence around that will also be easy to retort to.
Tell them you just feel more comfortable/more like yourself with long hair.
Also that personality decides the hair, hair doesn't change your personality. you wont be any different with extra hair on your head, other than maybe a little heavier :)