have you tried different types of cups? at 21 months, she might be excited by trying a big girl cup (no top or spout). obviously, try small amount first to minimize spillage. You can also try straw cups. Some kids get frustrated by the slow flow of sippies, and respond better to straw cups. Or, if she is used to the very slow flow of a bottle, she may prefer a slow flow sippy (the ones designed for infants flow much slower than the ones designed for older ones). Even the straw cups have very different flows. The ones that claim to be no-spill are pretty hard to drink out of. I test out the sippies after I buy them using water to get an understanding of what I am giving my kids and what their preferences are.
Or, you can try water only in the bottle, and milk in sippy cups. Eventually, she'll get bored with only water in the bottle but you aren't having the "no bottle" battle.
To get my older one to take milk in a cup instead of a bottle, we bought her special Elmo sippy cups, and they were for milk only. It worked pretty quickly (she was 15 months). You can try with whatever character is her favorite.
Thanks! I breastfed her for 12 months and the mistake I think I made was not transitioning to a sippy cup. I gave her a bottle instead and probably shouldn't have done that. O well, lesson learned... I'll know better for my new daughter in sept.
I personally have never been in your shoes as my kids were off bottles by 1 year. If i were you though id let her throw her fit and stand your ground. She will drink from the cup when she is thirsty enough. As far as weaning i started introducing sippy cups at 8 months and by 9-10 months my boys only got a bottle to go to sleep. I hope this helps you some and good luck!