She is going to grow up to look exactly like Bella, and he is not going to grow older than twenty-looking sixteen. Also, he is not going to be romantically attracted to her till she is thirteen or so, when it won't be an issue, since he will always be sixteen.
I do not care for Twilight but this nonsense about Jacob being sexually attracted to a baby has GOT TO STOP. People don't even know what pedophilia is anymore so they apply it to everything. "Oh, that guy is putting gum in his pocket where the clerk won't see, reaching behind that child to do so; he must be a pedophile!"
Supposedly (according to my Twihard friends) the imprinting doesn't mean that he'll fall in love with her romantically at the time of imprinting or ever. It all depends on what the other person wants/needs out of the other person. If Nessie were to want to shave her head and marry a punker named Spike, Jacob would only be there as a friend to carry her wedding bouquet.
However how *I* read it was that Jacob had soul mated himself to a baby, thus making her his love forever and ever, essentially taking away her free will to date as she pleased. He'd be there from birth to adulthood, so he'd have plenty of time to groom her into the perfect lover. Ultra creepy.
people are going to hate me for answering this....XD
He got ''imprinted''. Remember how Sam did to his wife? It's not a choice, it just happened. And it's not like he is attracted to Renesmee, it's more like destiny chose them to be soul mates. Plus, Jacob won't age...so he'll wait. Kinda weird, but that's basically it.