hi sean, glad to see you're getting all your ducks in a row! the breeder i got this girl from had her for three years, and bought her as an adult proven breeder then, so she's at least 5 years old, probably a little bit older. She's eating great, 2 rats every sunday. i would let her settle during the week, attempt to feed on sunday (as she's going to be skipping this meal prior to shipping). She's pretty stress-resistant, esp for a bp; i show her to kids and parents as an example of how huge (or not) they get to be as adults.
make sure your temps are correct this week while waiting, that way she can go straight into her new home upon arrival. after two or three days, she'll probably be looking for food. i'd recommend keeping her on a sunday schedule, but that's entirely up to you. after feeding, allow two days before handling to avoid the possibility of regurgitation or injury.