First off what happened to sex ed being a part of school? Second where is the common sense???
Ok- So yes typically woman can feel a man cummin inside of them.A mans penis usually gets larger right before it is about to cum and most woman can also feel that as well.
She is scared about being pregnant??? Well here is a clue for the both of you...You are only 18 and do not need a child..They do sell condoms over the counter at various stores, try to get a box!! Even if you do pull out there is a slim chance that she could get pregnant from the pre ejaculation. So that is not a safe method..
But like I said, yes women can feel it, and I doubt she is pregnant!!! Buy some friggin condoms before you try this again..