Should I be concerned???

M

My 4 month old has learned to roll from back to tummy but she hasn’t yet worked out how to roll from tummy to back. I place her on her back to sleep yet when I wake up she’s on her tummy.. is there any reason I should be concerned she’s doing this? I read somewhere that it’s only once they can roll both ways they can sleep on their tummy.. just not sure how accurate that information is 🤔