Are you POSITIVE she was fed rats, not mice, prior? Also, besides rats & mice smelling vastly different, fresh killed can freak out a snake too...same reason, much more scent. Always best to feed exactly what they had before. Also, snakes going into shed cycle (even before WE can see any changes, they 'know') often react this way to prey. I'd wait a week before trying again to offer food, so as to minimize stress.
It didn't help that she arrived chilled either, poor baby. If you're using only fresh-killed prey, you should have saved what she just refused in your freezer...
that would minimize & normalize the scent for her (unless she was previously on mice). And you can also thaw it in water, then blot on paper towel prior to
offering.