Kristen, I agree, I think Mia is doing fine. Angus is a very proficient roller, but still can't sit on his own. My friend has a bub who is 3 days younger than Angus and he sounds the same as Mia. She has just actually taken him to a paed for a review cause her mchn told her there was something wrong with him. The paed seen him yesterday and actually said he is just lazy and will do thnigs when he wants to! If it was me though, I would prob get a referral and see a paediatrician for a check-up just in case. They are the experts and I would trust what a paed says over anyone. No one knows your baby like you do, and I think for peace of mind I would get her checked! Just my opinion, but to save you worrying and stressing I think it might be worth it! Good Luck