I am by no means a corn expert, but I can tell you that I've had a somewhat similar experience with my female corn. She gets VERY excited during feeding time and she was the first snake to ever bite me. In your case though, it seems strange for a snake to just all of a sudden decide to be a voracious feeder, but I guess it's possible.

Also, my female got very pissy when she laid a clutch of slugs a few months back. I have no idea if this is the case with your snake, but I'm just throwing that out there. Does she look at all like she might be gravid?