I have a 3 1/2 year old girl also, and a 14 month old. I had them both off the bottle at 7 months. I think at whatever age you get them off the bottle its not any easy job. I used the Nuby 3 stage bottle it comes with a nipple that is similar to the regular bottle nipple. You use this first maybe for a couple days to a week. Then change the nipple to the square nipple, basically its a soft sippy cup nipple. Then you can change over to the hard sippy cups or regular cups. I think a 3 they should be using regular cups. TIP- If you can take her with you to the store show her the bottle and say something like "wow look at this bottle isn't it cool" or something to make it sound so special she will want it. Talk it up on the way home say wow you can try your new baba when we get home, aren't you soooo excited. Then when you get home ask her if she wants to try it! Good luck to everyone!!