Who am I supposed to be?

I found a friends blog to be extremely helpful. Since reading it, its as if something inside me is saying "Hey she has the right idea!" For a while now I see myself wanting to stay the way I was in high school. The way I dressed then and the way i acted. But now, it seems to be, well leaving me. I don't dress the same way with the devil may care attitude. I want to be a certain way but there's something telling me that, that isn't the correct way to be. I want to be the guy with the piercings, tattoos and band shirts that doesn't care what people say but I can't help but feel something is saying "No that's not who you are supposed to be." So I ask: Who am I supposed to be? Is this what being mature feels like? Its a scary feeling. I ask: Am i growing up? Am I now growing up into an adult? I've wanted to be mature for the longest time and said I would work on it and now if this is it happening right now then its scary because I thought it would take years but now its happening so quick. What is it?