Mackenzie didn't roll until about 7-8 months (from memory), she never crawled and walked at 13 months. She hated her stomoch and when we had her 12 month checkup wouldn't roll for the MCHN which worried her but not me! Rolling was how she got to the things she wanted until she walked which was very funny when she rolled a million miles an hour! They are all different and please don't compare to others in mothers group, it will only make you stress and worry.