I'd give her what she wants hun. When Sophie was around 3 weeks old she was feeding every 3hrs, i can't remember how much now but we got told she was having too much and we got told by the HV to "give her water" "play with her" and "take her for walks" to try and space the feeds out.
She was 3 weeks old, i didn't listen to her and fed Sophie when and how much she wanted and she cut out feeds herself an wasn't and still isn't overweight. She seemed to drink alot at first but soon settled onto 6oz bottles (again i can't remember exactly how old she was). and didn't drink anymore than that until she was around a year old and started to have 1 8oz bottle at bedtime (she still does). x