This is absolutely nutty! You are stressing over something that is completely crazy. Who says she HAS to be on a sippy cup 100% of the time at 12 months of age? Who says she must start drinking cows milk at 12 months? Who is giving you these ultimatums? If it is a pediatrician, switch. If it is a book, put it down. If it is a mother or mother-in-law, politely disregard their advice. I have four kids, and thank goodness I did not try to mother them "by the book", or by anyone else's rules. The oldest is now 23, youngest is 9, and they are happy, well-adjusted people because I followed my instincts instead of the "rules". There is nothing natural, normal or healthy about the rules you are attempting to follow. They are nothing but a modern-day invention. You said you "know it is better" for her to switch to a sippy cup, but that isn't true, because earlier in the exact same sentence you said that you don't really want to do it this early. There they are! Your mommy instincts! Go with them. You will never regret it, and your daughter will thank you for it.