High school awkwardness?

I'm a freshman girl and really insecure and shy. All my friends say I'm awkward. I just don't feel comfortable around most people, especially a group. I'm ok if I'm just hangin out w one friend on the weekend ya know, but sleepovers, parties, I just freeze up and become a total wallflower. I also get really quiet when they start talkin bout - I'm the only virgin in the group and don't really wanna hear my best friend talk about how hard her bf plowed her last night ya know? Any way I'm gettin off subject. How can I be more comfortable around people? Thanks