questions about RAT pregnancy!! HELP!

Dont worrie I didnt breed my hairless female.

I just have a few questions.

She is starting it get really fat around the sides, and she has not had any contact with my males at all.

The last time she seen a male rat was when she was in the petstore at around 1 month old. That was around December 20th.

Could she be pregnant by one of her brothers from the petstore??
I really am preying she isnt becaue I know hairless females have alot of risks giving birth.

HELP>

I don't have rats, but I looked up their gestational period and it's 21-23 days. So it doesn't seem possible that your rat is pregnant from a male she was with a month ago. Unless, of course, rats are one of those rare animals who can store sperm until they're ready to have a litter. Anybody out there know?