My nearly 13 month old is now going onto whole milk. She will normally have a bottle for nap time and bed time at night, with a mam bottle size 3 teat. I just know if I transition her to a sippy cup for milk at nap time she will not settle. She has a sippy cup in the day for water but her milk is more of a calming thing for her and helps her to sleep. Am I okay to keep her on the mam bottles for milk at nap and bed time with a mam bottle?