My youngest DD was a nursing baby until age 2 but I always gave her water in a bottle. She was coming on 3 years of age and still using the water bottle, did not want a sippy cup and raised a ruckus when she didn't have it. We wanted her to stop using the bottle and when her big girl 3rd birthday came up, we made a big deal about how 3 year old big girls use glasses and how big 3 year old girls don't use bottles, etc., etc. We kept asking her to try a pretty glass that we got for her and sometimes she would and sometimes not. The morning of her birthday the bottle was gone and in its place was her pretty glass because big girls don't use bottles. She rarely asked about it and it went over real well. I guess it was all that prebirthday advertising.