I weaned both mine at 12 months. If you are both happy with it, there is no need to stop, not that I'm saying anything is wrong with using formula. If she is wanting to use you as a pacifier just don't let her. When she stops eating delatch her. Find maybe a soothie blanket, my daughter had her "lovie" (it's like a little bear head with a tiny burb cloth size blanket atteached) and I would give it to her to hold onto while she fell asleep and go in and take once she was asleep. Try to remember to take it, although if she is moving around well it probably isn't too much of a concern. As far as the biting, if your reacting to it she sees that and thinks its funny. She can't understand that is hurting you, so she repeats the action to get your reaction. The first thing to do is not react. I know it's hard but try your best. If she keeps doing it, take off her your breast and wait a few minutes to give it back to her. She will eventually get the point if she bites she doesn't get to nurse.