I'm 35 weeks and I still sleep on my stomach. Just move whenever you're comfortable. During pregnancy, (and a lot near the end) sleep becomes precious and as long as you're comfortable you should be fine. :)
I am 13 weeks still comfortable sleeping on my tummy. If it's comfortable do it, if it isn't comfortable than don't do it but sounds like it's still comfortable for you so enjoy while you can :)
I'm a tummy sleeper too lol and I am 14 weeks and I can still kind of sleep on my stomach I just prop my sides with pillows lol you can do it till it's no longer comfortable... But sleeping on the left side is supposed to be the best