Fat Or Pregnant Molly?

So I bought a Molly from my LFS maybe 2 months ago, she's now looking quite large, but not huge and fairly square. I don't have any male mollies in the tank( community including a plecy, angelfish, platies and Pakistani loaches) though I have read they can store sperm/eggs. Can anyone tell me if she's pregnant or could have an illness, or is in fact just a greedy fatty? If pregnant I'll probably separate her to a nursery tank, but I'm not convinced she is...

Looking at the pics I'm fairly sure she is ready to drop fry fairly soon she looks healthy to me 

Hannahpops89 I just want to tell you to be careful with the plecs because they sometimes become aggressive toward mollies.  Angelfish and plecs are usually classified as semi-aggressive--not community like the mollies and plates.

Definitely pregnant. When you purchase mollies or other livebearers from the store you can always assume that they are pregnant. Generally stores don't split out the male and female livebearers and livebearers can hold sperm for almost 6 months.