When you first notice that she's pregnant, it could take 3 to 4 weeks until she actually gives birth. It looks like she still has a few weeks left before releasing the fry. Keep her eating and keep her stress free.
When she gets really fat, move her to an isolation tank with a breeding net if you want to keep all the fry. Otherwise leave her in the community tank but risk the fry getting eaten by her and other fish. If you have hiding places, they'll have a better chance of not getting eaten by hungry fish.
Feed the guppy fry small crushed flakes and brine shrimp. They have smaller mouths and need a smaller food source. If you want to raise them without worrying about them getting eaten, get a separate tank for them.
