If she's on the pill I'd be careful about having her take Plan B on top of that. Plan B can make her awfully sick by itself, on top of the pill it might be worse. I threw out plan B because of moral issues with how it works, I don't know ya'lls beliefs but that's something to consider.
As far as legal, it might be nice to as PDM said above remind us of your ages so we can feel comfortable giving advise.
