Their head is the most sensitive part of their body. When they curl into a ball, the head will be in the middle of that ball to insure it's safe. I have snakes that will shy away from a rat if it comes up to their nose and sniffs it. If they don't strike 5 mins after that, I take the rat out. You could try to feed small rats that way she won't feel as intimidated. But if she has a good feeding response, her being scared won't last long. Mine never shy away for longer than a week.