K.K.
My four girls all drink about that much everyday! They range in age from 7 to 2 and I'm currently potty training my 2 year old. We went through the same thing with all of them and my Doctor told me that they need to train their bladders to hold it. Not so long that's it's unhealthy but they need to train their bodys so they can wait longer periods of time between potty breaks! Two and 1/2 years of just going potty whenever they want is a big change! Give her time! My advice though is to take away the pull ups & diapers! get her a step stool to the potty so she ca go herself when she needs to at home and when you're out take her every ten minutes if you have to until she learns to hold it longer. Bring two or three outfits with you everywhere you go. I promise it will pay off.
All four of my girls were potty trained at different ages even though I started each one at the same time. My first and last ones seem to be the hardest!
Hope this helps! Email me if you have any questions.
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K.