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It's quite hard to tell from the pic but you need to have her on pregnancy watch for at least another 10 days. If she is showing bumps over her hips though then babies would likely arrive withing the next 5 days really.
Sometimes they do put on weight as they get lots of food when they are in their new homes. Can you get a pic looking down on her>
Take out any small enclosed huts or beds from the cage and any tubes need removed so they don't have babies in those. Give her loads of tissue bedding and leave her to make a nest maybe in one corner or give her a box with the bottom cut out. Geed some extras but not too much as you don't want too big pups in a young mum. If she does have babies then she will likely be in the nest all the time for the first 5 days or so and you need to leave her very quiet and undisturbed. Keep us posted on how she does.
If she has pups then advise the store and they normally make provisions for the pups ie extra cages and maybe food and stuff.