Hi, My Lo is 7 months old now. He can roll onto his tummy and support himself on his arms (but not back again) and is trying to sit up on his own but can only sit unaided for about 5 seconds. He isn't making any real attempt to crawl. I was just wondering what the average age is that babies start to crawl?. I know every baby is different but I'm just a bit worried that he should be sitting up by now and trying to crawl!!.