When will she roll over?

I keep trying. She is so close. This morning, she popped her bottom off the changing table pad and arched her back. She knows all the motions and is quite strong. For some reason, she just hasn’t put all the pieces together. Tonight, when Paul and Emily were here, we watched her go half way from both back to front, but she isn’t quite there. Hmmm. But she sits up like a champ!