We got rid of DD's at 12 months and she was the same as your DD, just having them twice a day and otherwise from a sippy cup. Our reasoning was that we didn't want 2 having bottles at the same time. It was seriously so easy and not a big deal at all, we just gave her a sippy cup of milk instead. She didn't even seem to notice since she already was used to the sippy cup and in fact, I think she liked it more because she was able to drink the milk faster.