If the guy and the pet store had her previously, they most likely tried feeding her either mice or rats and if she's already been in your care a few weeks she's probably started to de-stress somewhat and think about getting hungry. I'll bet you have a pretty good chance she'll eat for you.

I stopped off yesterday in the pet store that ticked me off before with their ball python husbandry (before several of you joined, so you may have missed it) and saw once again several juvie balls (including 2 that looked like new hatchlings) being housed in the same tank with no hides, no water, no heat mat. This time, though, to make it worse, there was a bigger bp in a separate tank (probably 800 g or so) with no hides, no water, and two big heat rocks -- the poor thing was curled up in the back corner, trying to hide. I wanted to bring him home, but didn't want to support the store and their treatment of him. I'll bet he was turned in to them because somebody didn't want him anymore and they just set him right up to sell. What makes it even worse to me is that the rodent cages actually had hides, as did a couple of the lizards, but not the poor bp's.