Ccan she be preggo?!?

E andM my girlfriend have been dating for a while and we went to the florida keys this spring break. We were messing around and we were rubbing our bare "parts" on each other. I had a small amount of simen on the tip of my "part and was rubbing it between her "parts" lips(no actual penetraion). Can she become pregogo from that? She was supposed to have her period hyesterday. She is young and they are inconsistant, but with the time of her period being close, and the condtions i mentioned above, is it possible? I unserstand abesenece is the bst form of birth control, i just need to know the chances of her getting pregnant