Kinda iffy.. I see no gravid spot... and TBH, you usually see a gravid on platies... Also if she is and if she's close her blely is square off when shes ready to drop.. she may alo be constipated.. which it looks like to me as I see no gravid spot..
Clearer, better pictures will help a lot.
I can't give a difinitive answer with that picture. Sometime gravid spots are "pushed" into there white belly area. I've had that before
I'd say she's preggers. But you'd be doing the fry a great diservice by removeing them from the main tank. Fry are incredibly smart, and will avoid being eaten on their own provided you leave them be. unless you have angles or some other notorious fry eating species in there, they should be fine. they will grow fast if well fed, and able to school with the adult plattys in about 2 weeks. removeing them would not also require another full sized tank set-up, but in my observation i have noticed adult fish raised outside of a community atmosphere develope at a slower rate on a physical and mental level, i suspect this is due to them not haveing to use thier instinctual traits to avoid danger as they grow up in a safe, no hazard environment. My observations are on guppy fish, not platys, and im not a marine biologist. But I'd suggest dimming the lights and letting the fry do what they do.
It looks pretty pregnant. However, I am not 100 percent sure, because you can't see a gravid spot with that image. Try using the macro setting on your camera. It's the setting with the flower on it