Stick to 7 days til she's about 2 years old, increasing prey size accordingly as she grows. The prey item should be 10-15% of the snake's empty weight (weigh her after she poops). I generally go to a 2 week feeding schedule at around 2 years of age, and 3 weeks once they are eating jumbo rats.
My BP was on a 7 day schedule until he started eating medium rats. He's on a 2 week schedule from here on out.