Sleeping on Belly.... Paranoid Mom here

My baby girl has always been a good sleeper. She has been sleeping through the night since 3 months. Always on her back no issue. About a week ago she has started to roll in her sleep she's 7 months ( she rolls never in her sleep) and now sleeps all night on her belly. I've been a nervous wreck. I stopped trying to flip her back, she just got frustrated and flipped back. Are other babies sleeping on their bellies? I just want to be at peace with this and not a nervous wreck every night. She keeps her head to the side but I caught her a couple times face down. So scary. Any advice?