They say back is best & most safe for sleeping (reduce risk of SIDS)

Well my 13w old has now started rolling back-belly while sleeping. She cannot roll belly-back yet awake or asleep.

This has me paranoid and not getting much sleep because I keep waking up constantly to roll her back. But now I'm getting these moms saying tummy sleeping is fine? I'm confused because she can't roll from her tummy to her back if she needs to.

Is it fine or is it not? Never get a clear cut answer.

* she sleeps in her own bed

** additional question: should I not put her in a sleep sack anymore for bedtime? Any footed pajamas would be too warm.