My 10mo is a tummy sleeper and has been since around 6 months old. Always put down on her back and rolls over immediately. At first I rolled her back, now leave her. Sometimes she has her face down or leaning into the matress. I watch closely and she moves it after a few seconds, should I be as worried as I am? She has no blankets, sleeps in an ergo sleeping bag. I follow safe sleep 100%, I’m wondering what I can do about her face down antics.. please help

Most babies will be rolling over by 5 months. This is very normal as babies grow & become stronger.
Many babies then prefer to sleep on their tummy.
This is not something that needs to be stopped. It is important to make her new environment as safe as possible.

Also ensure that the mattress is firm & flat & there is nothing soft or loose in her cot.
The firmness of the mattress is particularly important if baby is “face planting”.
Some babies do this at times, but most change that position after a short period.
Ensure arms are free in the sleeping bag you are using.

Red Nose has the following information now that your baby is starting to roll.

Give baby extra tummy time to play when awake and supervised as this helps baby to develop stronger neck and upper body muscles which in turn enables them to roll back over.
Make sure that baby is on a firm and well-fitting mattress that is flat (not tilted or elevated).
Make sure that baby’s face and head remains uncovered (do not use lambswool, doonas, pillows, cot bumpers or soft toys)

As babies grow and develop they become very active and learn to roll around the cot.
At this time, continue to put them on the back at the start of sleep time, but let them find their own position of comfort.
By this stage it is not necessary to wake during the night to turn baby over to the back position

Do not use any devices designed to keep baby in a particular sleep position.
https://rednose.org.au/article/what-do-we-do-now-that-a-baby-has-started-to-roll-over