Is Pregnancy Possible Despite Taking Plan-B After Unprotected Sex?

Me and my girlfriend had unprotected sex 4 days ago, but it wasn't really 'sex'. I just put my penis inside her for maybe 5 minutes. Not enough to feel anything. We had unprotected sex again yesterday, and she took the Plan-B pill 30 minutes ago. She is not ovulating nor is she on her period. She expects her period in 3 weeks. What are the chances of her getting pregnant?