I bet if you skip feeding for a few weeks and then offer a rat, she'll take it. If not, wait another week or so and try again. If you wait her out, I'm guessing you can convert her. I don't have nearly as much experience as most on this site, but I have read probably hundreds of threads here and on other forums about people switching food. I'd say maybe 1/1000 (or less) just can't be switched... due to an extremely picky snake. It seems most people give in too soon and just revert back to what they were previously doing. Keep an eye on her weight, and if she isn't losing, and is still acting well, wait her out. When she's hungry enough, she'll eat a rat.