Most babies will begin the crawling phase at 6 months of age but some babies may not begin crawling around until 10 months old.
Also some babies never even crawl but instead skip the crawling and just begin pulling themselves up onto things such as coffee tables, couches, chairs and other furniture.
It's very normal if a baby doesn't crawl but most babies do crawl and you should notice the crawling at 6 to 10 months of age if the baby does crawl.