late menstrual cycle but no sex!

two weeks ago (may, 8, 2007) my girlfriend and i mutually masturbated and i fingered her but thats as far as it went. she was due for her period two days ago, so on may 21st, and it still hasnt come yet. i am almost 100% certain i did not get any semen in or around her vagina but this is the first time shes been late in a long time. and that was the first time ive gone down on her. my question is that if even a little bit of semen was on my finger would it be enough to impregnate her? and could my sperm have made its way all the way inside her from even around her vagina? we are both pretty sure that no semen got inside her because we did not have sex and all i did was finger her. could she be pregnant???

sperm are pretty powerful, but alot of things can cause a period to be late.
stress, medications, sickness.. and the list goes on and on.

give it a little more time. if you two are that worried head down to planned parenthood and get tested or get a home pregnancy test after she's been 5 days late, they are most accurate then.