Does my girlfriend having hpv mean i might get oral cancer?

Yes and no: Her hpv has to transmit to your mouth first, through whatever the route; then the types of hpv have to be hpv 16 or 18; then you have to develop hpv-infected lesions inside your mouth; then maybe 1.5 years later, you have a peculair lesion/mass; then may be it's a cancer(or maybe not). Anyway, you have to have all those factors collectively happen to you then you have a chance.

Possible: Hpv infection is associated with oral cancer, penile cancer, anal cancer and cervical cancer. Most people who get hpv do not develop cancer, but it is a risk factor.