I agree you should ask her father's permission to marry her. I did and he thought I was crazy as he was under the impression that sort of thing didn't happen anymore (way back then)

I can give the impression of the grandfather of a child who has parents that live together and aren't married. While I was more than a little pissed at first, once the baby was born and I accepted that he didn't have anything to do with the fact that his parents kinda had things backwards when it came to marriage and parenting, he's actually kinda neat. The father of the child though has yet to say word one to me and that disappoints me greatly.

Do the right thing though and marry her for love, not just because of your child please!