Baby sleeping flat on face??

Sydney
My daughter will be 8 months old on the 17th and recently she's begun sleeping on her tummy, but she is literally face down. She doesn't turn her head to the side when she sleeps. 
She sleeps like a rock all night long but I worry so much that I am up every 2 hours or so going into her room to flip her back over. 
She started sleeping in a crib in her own room about a month ago and I've been so paranoid ever since. Also, being 21 weeks pregnant isn't helping me calm down😫
Hubby is telling me that she isn't going to put herself into a position where she can't breath, and I know he is right but I'm still looking for reassurance... does anyone else's baby do this?