Why isnt my Common Boa Pooping?

  I have had my common boa for about 3 weeks now and she hasn't pooped once. She is about 7 weeks old, 20 inches long and is feeding on 2 fuzzies or 1 small mouse a week. Should i be worried about this?
you can soke him in warm warter it will help most reptials poop. you shoud use reptabark or newspaper as beding.