It might have been too cool... If the head and body aren't hot enough, the snake won't even recognize it as prey. They hunt mostly by heat signature, so if it's cool it looks like nothing to them. Smell is secondary and they barely use their sight to hunt at all, I think. Using a hair dryer or heat lamp to warm mostly the head and also the body really helps a lot. Both should feel warm to the touch and the head warmer than the body.

We're starting to get near the end of the breeding season now, but I don't think it's 'officially' over until April or so, when girls start really laying eggs. Some snakes eat all the way through, some stop in November or October and don't start up again until spring. Was she eating at the store you got her from?