Yuki,
If you post a picture we could possibly tell you if she's pregnant. Also, I would get a breeder of some sort and get LOTS of plants in the tank if you don't already have them (fake or real, doesn't matter). Mollies and other fish WILL eat the babies, so they need to have places to hide if any of them are to survive long enough for you to find them.
I currently have 30 2-month old black molly babies and 7

1-month old silver molly babies. The second batch was born at night, so only 7 made it to the morning, and since myt mollies ate half my frill plants, the babies didn't have enough hiding places. They were in a net breeder for about a month and now they are in my main tank with a divider. The best food for them at first will be either live or frozen (defrost in aquarium water first) baby brine shrimp. You can also take the regular flakes, put some in a plastic baggie and keep crushing with your fingers untill you literally make a powder. I feed mine both the shrimp and the flakes. Oh, and although they only need small amounts of food, like what you can pick up with a wet toothpick, you will need to feed them frequently. Mine eat 3-4 times a day. Congratulations, good luck, and have fun!
Izabela