- Try feeding her in her home enclosure. There is no reason to pull her out of her home, likely making her feel uncomfortable and stressed, in order to feed her.
- Try a smaller rat than the guy at the store recommended.
- How do you know she's hungry? When's the last time she ate? They can go for quite some time (many months) without eating - especially after moving to a new environment.
- "Dancing around her cage" could also be a sign of stress. A comfortable ball python is pretty much a pet rock. I'd deep dive into your setup if I were you and make sure you've got it dialed in for her. Ask if you need help with this.
- How big is she? I'm going to assume that she's adult size since you mentioned not being gravid and it not being mating season (which it actually is for most breeders).