Is this normal?
Yes.

As long as she is strong enough to strike she is not too weak to eat. A week is not a long time for a BP to go without eating.

I wouldn't worry about this but while you're here...

1)How much does the snake weigh?

2)What are your hotspot and ambient temps at? How are the temps controlled?

3)What is the humidity at?

4)What is the hide like?

5)What temp is the food item when you offer it?

6)What size of food item are you offering?