Don't be too upset. Do you know the account in the bible of the Ethiopian Eunuch? As soon as he found out about God he got baptized. There was no waiting period, zillion questions or approval from a bunch of men (or elders.) They did not have guidelines on what he should wear etc... It's all silly, don't be so mad. Do you really want to be a JW? If so, they will require you to have a normal hair color (what they think is normal) take out your piercings unless they are in your ears and so on. I always wanted my nose pierced and my belly button but never could. I can now, but I don't even care anymore.
Be yourself and don't let other people dictate to you what you should look like or wear. If you area true Christian, the only thing that really matters is your actions and faith.
Be young and have fun, cause you are only young once. I missed out on so much, don't do the same thing.