Most of the skaters I see at my skatepark wear helmets, and even skaters who are riding around town, but I live in Oregon, where skateboarding is mostly accepted, and you do it at your own risk (no suing the city because you're an idiot and bit a curb after skating through a construction zone - it happens). So if you don't wear a helmet, and you end up donating your brains to the pavement, well ... good for you? So most kids here wear helmets.
I would like to encourage you to do the same. This is a pulpit I'm happy to preach from. If you aren't wearing a helmet because you don't want to mess up your hair, or because they're uncomfortable, then grow up! Most likely your hair looks FAR nastier than you think it does, and no one will care how nice you hair looks if you end up a vegetable. And it's VERY easy to scramble your brain - shockingly easy, in fact. Our brains are soft and vulnerable, and rumor has it they're important! Read Do I Need to Wear a Helmet? for more.