Everywhere I've looked it seems to be that babies should be able to sit by about 6 months but my ds is nearly 8 months corrected and still can't sit alone. Should I be worried about this as he's already trying to crawl (albeit backwards) and I know they really have to be able to sit before crawling??? He had assymetrical IUGR (head bigger than body) so I'm not sure if this is anything to do with it? Does anyone have any experience with this or have a baby that sat late?