To be worried?

[Autumnlily14]

So my 5 1/2 month old has only rolled all the way over once. She will sit up with help and for a few seconds on her own very occasionally. I try doing tummy time and sitting when I can which admittedly in the last few weeks hasn't been as often as I'd like.
I know 5 months is early and I shouldn't compare but my son was sitting at 12/16 weeks all by himself. I'm also wondering what I do when it gets to 6 months and she isn't sitting on her own as that's one of the requirements for weaning?

She was also born just under 3 weeks early so would be just under 5 months corrected.

My DD didn’t sit by herself until 9 months (didn’t even roll until 8.5 months!) but still weaned fine as she could sit supported in her highchair.

@ForeverTired89 i did wonder about this but on the nhs it says that it's a sign of readiness then sitting