Well, that's the thing about hpv. You would have a 99% chance of not ever getting any symptom whatsoever. But, yes, even with condoms you would spread it to any woman you ever had sex with and therefore she would have to get colposcopy's, possibly a leep and then pap smear's every three months for two years after and (god forbid) cervical cancer. And then everyone she would have sex with after that would also be in the same situation.
Is your girlfriend getting a leep or anything of the sort? You see, sometimes (although hpv never leaves your body) after the leep and when her paps start coming back normal again it is possible that you wont contract it. But, no one knows and you wont know if you actually have it or not.
The thing about hpv is that it forces you to make a commitment before you can have sex. A bad thing? That just depends on how you want to live your life. Ultimately no one should be having casual sex anyway and if you have any morals whatsoever, this now forces you (the person who has hpv) to live a life that is not promiscuos.
All I can say is if you aren't going to commit to this girl then tell her exactly what you just told us. If you like her then why don't you try to get to know her better and see if there is a future for you two. 21 or not, that doesn't mean you need to go out and have sex with all kinds of women. It only takes one that you love to make you happy.
But, don't lead her on if you aren't going to commit and don't cheat on her. If you are going to have sex with someone else then just break up with her. Don't disrespect her because something was given to her that could have been given to anyone. It could happen to you to. You already could be infected and not know, so you really shouldn't hold this against her. But, I also understand why you would be weary of having sex with her.
Whatever you decide, if you do have sex with her, make sure you do the right thing and before you ever have sex with anyone else you tell them you are a carrier for hpv. If not, it isn't fair that they didn't have a choice (which she kindly gave you and you would need to do the same to someone else), and it could be a death sentence for them. Lots of women for some reason do not get pap smears and they could have progressive cervical cancer before they even knew anything was wrong.
So, use your head and good luck. Just please don't hurt your girlfriend as she does not deserve it. She was responsible and kind enough to not just go ahead and have sex with you and lots of people would never do that.