When are toddlers able to sit up from laying on their back without having to roll first

[Sarahsooosooo1]

Just wondering (anxious mum here), when toddler are able to pull themselves up from laying on their back using just their tummy? My 18 month old has to roll onto his side and push up with his arms to get up from laying on back. Probably entirely normal! But just wondering. Thank you

Mine is trying but doesn't succeed often..a bit better when on soft surfaces.
He is 20 months old. But I don't know when they are supposed to do it to be honest.

I did a bit of research last night, and turns out it’s totally normal for a long time yet

Good to know :)