I’m not sure what breed she is, but one month is very young for a rabbit to be away from their mother. Some of the more experienced members might have some advice relating to care of a rabbit that young.
If she is in fact only a month old, it is very likely that she could be either male or female, as it is quite hard to tell so young, and rabbits are often misexed.

She’s young, but she looks older than 4 weeks. Maybe between 6-8 weeks. It’s hard to tell when they are this small, but her head and ear shape suggest a dwarf breed and potentially lop ears.

Yes, hard to tell that young, but she’s very cute. 🙂

If you are new to bunny ownership, there is lots of useful info on care (diet, housing, etc.) in the bunny info tabs at the top of this page. 🙂

Coming from a pet store, she’s most likely some sort of mix. As LBJ said, she might have some lop in her, those ears are pretty chunky. She’s adorable! 😀

Also agree with Bu about gender. Don’t have your heart set on it being a girl, bunnies this young are difficult to sex even for breeders or vets, a pet store employee is unlikely to get it right (at least not on purpose). It’s pretty much toss-up at this point.

Even the rescues near me sometimes don’t get the sexes right when they end up with baby buns, which is why when they plan to keep some of them together, they sex them twice (a few weeks apart).