material girl wrote:As far as I know you should be covered from about a day after she takes it(Id imagine you have to give it 24 hours so the body can absorb the change its making)...
Hope it all works out well.
Um, no, not if it's birth control pills. Generally, you're told that it's a month before they become effective. If it's a barrier form such as a diaphragm then it's effective whenever you use it. Of course barrier forms, just like all forms of birth control except for absolute and complete abstinence, have a failure rate. Nothing's perfect, but gambling with the odds is not a great or smart thing to do.
One thing that affects the odds is where in her cycle she was, e. g. right before her period, right after, two weeks after, etc. This is in conjunction with what's known as the rhythm method, which is a horribly ineffective means of birth control but it does give an idea of odds. Intercourse at or near the two week mark after the end of her period means you're very close to the time of ovulation, so the chances of conception are higher. But sperm can live up to two weeks, I understand, so that means, essentially, that the first two and a half weeks after her period ends are potentially dangerous in terms of conception. As for after the magical two week mark, that's not a perfect indicator, either, as ovulation times can vary. See
http://www.pamf.org/teen/sex/birthcontrol/rhythmmethod.html for more information on the rhythm method.
Anyway, just like material girl, I'm no doctor. If you are concerned, get a home pregnancy test and follow its directions perfectly to be sure. And if you want to be extra sure, go for an appointment with the doctor as well. If she's not pregnant, consider this a warning and never, ever do it again -- tossing your future around because you got caught up in the moment is, well, immature at best. Sorry if that doesn't sound very nice, but it's true. And, of course, if she is pregnant, you've got a lot more to think about it.
For your sakes, and for the sake of your futures and the future of any kids you may have, either together or with other partners, I hope it turns out as good for you as it can at this stage of the game.