My OTTB used to refuse all the time and it would take a while for me to get him over the jump without an issue. I am training him to be an event horse and I knew that all the jumps out on the xcountry course or in the stadium ring would create a problem if he wouldn't jump new fences. It took a while to figure out that I was the problem, not him. He wasn't scared of the new jumps, we was unsure what to do because I was not committing to the jumps. Now, when we are going torwards a new jump and I feel him start to draw back, I tap him with my heels every stride going torwards the jump and he jumps. He listens because I am telling him we are going not saying "well, if you want to..."
Try to committ to the jump and ride every step of the way, it might boost her confidence if you ride more confidently. Good luck.