E.S.
My son was the same age as your daughter when we started to introduce formula...and he hated it! The trick that worked for me (recommended by a friend) was to add a tablespoon of Karo syrup to the formula bottles. I wouldn't say he loved the formula then, but would definitely take it without too much fuss. I then used less & less Karo syrup with each formula bottle and over the course of a week or so, he took the formula with no problems at all. Hope that helps!