it's fine for them to sleep on there tummy once they are able to turn there head so it's not face down in the mattress.

yeah! my son is 7 months and sleeps like this every night, and has done since around 5 months. i used to move him onto his back but he always went onto his front again! if there's no blankets near his face he should be fine hun. they must find it comfortable😋 xx