Finally ... Sweet Pea rolled over! She took her time about it, though. Yesterday I put her on her tummy, and after about 5 minutes she rolled her head and shoulders to the side and just lay there for a while. Like, 20 minutes! I was just about to throw in the towel and pick her up when -- flop! -- she rolled her hips over too. Whew!
She did it again this morning, when I put her down for some tummy time in her crib. But it was much quicker, so maybe she's getting the hang of it.
So, all three kids did it at different times. Little Man: one and a half months. CC: two and a half months. Sweet Pea: three and a half months.