DD is 7 months and doesn't roll to get around. She did tummy to back a few times on our bed when she was 4ish months but hasn't really done it since. She'll do back to tummy a couple times a day. She can sit unassisted for long periods of time and will pass an object from one hand to another so I don't think I should be that concerned? The doctor said it may be because she's chunky but I don't know. DS was just as fat and at this age I had to put up barricades cuz he was all over the place. She just doesn't seem that motivate no matte what toy I tempt her with. Ease my mind mamas!!