It doesn't hurt the baby unless it hurts you, well your stomach. You should be fine till your future along. Then you'll not be able to because it will hurt lol
I'm 22 weeks and I still sleep on my stomach. As long as it's still comfortable for you, you're fine.
I'm 28 weeks and still sleep on my stomach with no pain or anything so until it hurts or is uncomfortable I will sleep on my stomach until it's uncomfortable for me
My midwife told me its safe as long as I'm comfortable whenever I start hurting the baby will feel it too currently 17 weeks