I agree with the above. Additionally, if you're quite paranoid about it, you can try giving it a bath in very shallow (only a little over it's body), warm (75-85 degrees F) water for about ten minutes. If she hasn't pooped yet, this should trigger a reflex that will cause her to poop. Sounds odd, I know, but it usually works. Don't be upset if she still doesn't produce anything, she's probably done it already. Also, for the lighter coloured young ones, you can typically hold them up to the light and see if there are any shadows near their cloaca, which would indicate the need to poop. If she looks distended (there's a nice big bulge at her cloaca, there are shadows there, and she's attempting to poop in the bath but can't get it out), then that might be reason to call a vet, but it's most likely nothing to worry about.