If you've had her two weeks, she should be plenty settled. I like to put the frozen rodent on the top of the ball python's tank while it's thawing, so the ball python smells it. I warm the rodent for five minutes under a heat lamp, with the nose closest to the heat. You can also use a hair dryer. (If you use a heat lamp, set a timer. I'm forgetful, and the result is overheated rodents. I have to let those cool back down, and then they usually explode when the snake constricts. YUCK.) For well-established adults, I just hold the mouse by the tail and just lower it down. For picky eaters, I use tongs, so my hand doesn't scare them. And then I can do the zombie mouse dance if necessary, trying to convince the snake that the f/t rodent is actually live prey.

(Most snakes you'd use tongs to avoid getting bitten. Ball pythons you use tongs to avoid scaring the snake. Go figure.)

The answer to re-freezing is MAYBE, IT DEPENDS. It depends on how quickly you thawed it, how long you left it out, and how you warmed it up. Think of thawing a chicken breast and leaving it out on the cutting board for two hours... If you thaw quickly, under running water, you didn't leave it out long, and you only warm up the nose of the rodent, then yes, you can absolutely safely freeze and re-heat ONCE. ONLY ONCE. If you thaw slowly, leave it out for a long period of time, and THENaccidentally warm more than just the surface of the rodent, I recommend throwing it away.

Is she eating food the corn can eat? Feed the corn second. It's always much nicer to have a garbage disposal snake take care of the leftover. Otherwise, my favorite way to throw it out f/t is to give it an honorable burial in the front garden, where the dogs don't go and can't dig it up. I put a rock over the top to keep cats away. Otherwise, I wrap it in a plastic bag and throw it in a dumpster, far, far away from the house. Because I hate that smell. Hate it.