S.L.
I had a friend absolutely FLIP OUT because her baby had learned to roll over and she found him sleeping on his tummy. She thought for sure he was going to die of SIDS at that instant. But once they can roll over, they get too choose their sleeping position. The "back to bed" is just for newborns. Both my boys became stomach sleepers, too. After all, isn't the typical baby sleeping position on their tummy with their legs tucked under and their bum in the air? It's so cute! My 23 month old still does that.