Hi - My DS rolled everywhere until just after 12 months. He actually has never crawled at all, but instead started bum shuffling around 13 months and not until around 16 months did he start pulling himself up on things and was walking just after 17months. So I wouldn't be too worried as there is no 'normal' when it comes to this. I was told that crawling is pretty much the only developmental stage that all babies don't necessarily do. I hope this is a little reassuring for you.