Can she get pregnant?!?!?!?!?!?! HELP!!!!!?

hey all ... i need to be a bit detail ... sorry abt it ... pls help!! uh .. i n my gf are 17 years old.. her periods ended tuesday - 21st june,, n we "tried" havin sex on thursday ... uh wen i say tried i meant this - i just put my penis not more than halfway through her vagina, for a couple of seconds n i put it in just once. i din *** inside her .. she was not ovulating at that time ... i don think my pre ejaculation contained sperms in it coz i had masturbated long ago (days ago) ... i din wear a condom ... n i dont know if i pre ejaculated inside her ... but m sure i din ejaculate inside her coz i later masturbated after tat "act" ... Can she get pregnant??? HELP PLS!!!