Is it normal to only roll to the side to sit up?

My son is almost 11 months and I just noticed that he rolls to the side to sit up (when he’d been lying down.) As opposed to sitting straight up, if that makes sense? I’m wondering if that’s normal bc their little muscles are still new or if this is something I need to keep an eye on. He gets around beautifully- Sits well, rolls both ways, crawls, stands.. If he’s lying in bed though, between my partner and I closely on each side, he looks like a turtle on its back trying to get up without being able to roll to the side and use his hands to help him up. Is this normal? Thanks in advance!! ☺️