And the little one said "roll over"

Emerson is 2 months old today. Yesterday she rolled over for the third time in her life (the other two times were a couple weeks ago). I'm not sure when it actually counts as rolling over, though. All 3 times have been on accident - she was lying on her stomach and lifting her head up. Sometimes when she lifts up her head it starts wobbling back and forth and occasionally the momentum as built up so much that it tips her over onto her back.