I'm not a virgin, but I'm nearing the first time with my boyfriend and it feels really different. The past times I've been intimate with a guy I've never really been nervous and I kinda just went with it. And now I'm  nervous, but it might be a good nervous... The guys I was with before were just flings but now that I'm in a serious relationship and we're waiting to have sex, I'm just nervous... Why do I feel like this?