So DS3 is coming up to 11 months old. He's been rolling over since 5 months, able to push up to sitting from lying down, rotates round on the spot - but is not crawling. He wants to, gets in position and either goes backwards (and gives up) or flops on his belly rather than cross crawl. DS1 was crawling at 8 months, DS2 at 6 months and they both went straight into it so I'm unsure if this is something I should be worried about or not. He loves his jumperoo and likes to stand and put weight on his feet so I don't think there are physical development issues with his legs. How late did your late crawlers start moving?