I agree, sounds like a defensive strike to me. I have actually never had one of my ball pythons coil a rat without killing it, but I have seen them strike at, and injure a rat that they are not interested in eating, but do not want the rat near them either.
I suggest waiting until the snake is hungry and try again. Do not leave the rat in the enclosure for longer then 45 min or so, because it will just stress her out anyways.
Hope this helps.