Why doesn't my girlfriend like being a little more intimate?

We've been dating for 7 months. She's 16 I'm 17. So basically what she tells me is that she thinks it's gross to even make out or anything and it's really starting to bother me. Don't get me wrong I really like her. I'm not just dating her to get some. If I was I would have been gone 6 months ago. Ha. But anyway some of her close guy friends tell her that she needs to try and be more intimate with me or I will leave because let's face it.. That's the mind set of most guys. And I didn't really think I was like that but I am sort of. I feel like I'm dating a little girl that thinks boys still have cooties..? It's getting ridiculous. When we do make out she acts like it was something she never wanted to do and is glad she got it over with. So my question is why is she being like this? I kind of doubt that she thinks it's gross but maybe that really is the reason. I know she likes me and has almost completely opened up to me but I still can't figure out why she doesn't want to take our relationship to the next level. I almost feel like just her friend instead of her boyfriend.