If she can roll on her own and she is in a sleep sack that does not restrict her arms, she should be fine. Mine did the same at that age and she is now a happy tummy sleeper.

How hard is the mattress she is sleeping on? Her breathing is more likely to restricted if it is a soft one as her face is more like to push the mattress up around her face.

Can see roll over? If yes then she should be fine. If not and you are worried about it maybe try baby postioner.

If she’s able to roll back and fourth herself, she should be ok. Always seek professional advice though like from your maternal nurse if not confident