Hey Jesus! how's it going?
Well mate, you have a tough one here. First let me tell you that yes, I've been in your position, all my classmates have had sex at least once (some of them constantly do, but that is just none of our business) and I am still a virgin (17, in college, hard to believe, huh?) Well, the thing is, what is more important for you: to be "cool" and be accepted for something so.... pointless as being virgin or not, or your girlfriend?
It will be hard for you if she doesn't want to have sex, and I understand her (she may have an ethnic/religious backround that she wants to be loyal to), and it will be hard to convince her. You sound like you really want to be with her, so try giving her some time. At the end, you won't die if you have no sex!
The first time is somthing tough for some people, especially if they have, as I already told you, an ethnic or religious backround. Try talking with her about her reasons, I mean come on, just because she doesn't wants is not true! Also, try not to point fingers. Sometimes when we're sad or disappointed we use to sound is if it is the other people's fault, when we just want to have answers. Be sweet and kind if you'll talk to her.
And, well, to your friends, your sex life is none of THEIR business either. I mean, they can brag all they want about their first time being the best thing and the orgasm they both had was HUGE and she moaned like crazy and they shot a big load, and whatever, but you never know if it is true or not, unless you WERE there. So, chill out. And heh, most of the times the first time is not the best time. How can it be, if you're totally unexperienced?
So more simple: talk to her, kindly and softly about her reasons and try to work out a way she will be comfortable and you can still get the experience. And just answer your friends with a 'none of your business' if the ask. At the end, it IS none of their business!!
Good luck my friend, and keep us posted!
-Jean