Yeah I'd say she is. I have a Dalmatian molly I bought from a pet shop a month ago, she was sleek looking when I got her but now she's starting to square off. She isn't all that fat either, just a little chubby looking so if I had to guess I'd say your's is about a week or 2 behind mine and she probably won't get very fat. Did you get her recently? I've heard that most pet shop mollies (That are dropping their first fry don't get very big and have a minimal number of fry)