You aren't a bad mom!!
Bear in mind, Science Diet has loads of chemical additives that add fake tasty components. Its like offering McDonalds or fresh veggies to a child. Which one is he going to pick??
You are going to have to train her to eat what you want. I worked with a holistic pet food company that sold all the premium brands and Candidae was not the most pallettable of the kibbles, anyway. Its pretty bland and bigger dogs seem to like it better then small breeds.
Solid Gold Wee Bits was usually enjoyed by my small breed clients, as is Timberwolf and Orijen. See if you can get some samples of other premium brands before resigning to feeding Science Diet. You might try mixing a few tsp of warm chicken broth into the kibble or using a grain free wet food mixed into your kibble.
Have you thought about trying raw?? Some very picky eaters got right into raw eating and it is so, so healthy. Its what I feed!!