Just call me the obsessed-with-sleep-mommy. I'll move on to other topics, I swear. But for now....

MY LO (5 months old) has been rolling over to sleep on her tummy lately. It appears that she's most comfortable that way. It's the only time that she can get herself back to sleep. Like, she'll start crying but then roll over to her tummy and immediately fall back to sleep. I usually flip her around to her back again, tummy sleeping makes me nervous. But as soon as I do she becomes very aggitated (she's probably thinking, "wth, don't you know how much energy it takes me to roll to my tummy!!?!") and usually wakes up shortly after.

Do you have a tummy sleeper? What age did they start? Should I be allowing her to sleep the way she's most comfortable? I don't know when a baby is ok to sleep like that, without it affecting their breathing.