Uptight? Think so?

I am a hot, very stylish, smart 19 year old girl. I work at a company as an accounts payable clerk and go to school. These are all good qualities, that should make me free of any inhibitions, but how come I'm soooo BoRiNg and scared to socialize? I can't just loosen up and party without being the responsible grandma? I do this every once in a BiG Blue Moon and I still don't fully act my goofy self! I dance really well, but I'm embarred to, like people won't take me seriously if I do. I don't smoke, I don't drink, and I don't really like clubs! I want to have fun and stop worrying, like I'm 50, so much! Why do I do this? What can I do to be more outgoing and stop being so miserable?