How long has it been since shes stopped eating?
She could just be fasting. Theres many reasons why snakes to this, it can be maturing, hormones, changes in enviroment, etc.
I wouldnt worry too much.
If you must ...feed her live, if she doesnt take a live rodent shes most likey just fasting. Offer her food weekly until she comes out of it. One day she will eat again.