At that age, feeding every five days is fine...and every seven days is fine as well. Whatever works best for you and whatever the snake is willing to do.

What you need to look at more closely is the size of the prey you are offering. Pinky mice are like snacks, even to a baby BP. They're just too small. I know it can seem scary because their heads are so tiny, but trust me, they can take much larger prey. A small adult mouse would probably work just fine.