When did your baby start crawling?

I know it's not good to compare babies but I'm just curious. My cousin gave birth to a baby boy April 30th and I gave birth to a girl May 5th. They are very close in age lol. Her little boy is 7 months like my baby and he's already crawling. Her baby started rolling at 4 months sat by 6 and has two bottom teeth. Oh, and her baby is already saying mama and dada. My baby started rolling and sitting at 6 months and has no teeth, she likes to yap but won't say mama or dada. Anyway, just wanna know when your baby started crawling? My baby doesn't seem to have any interested in doing that just yet! Not worried about it though, I know all babies are different. It's just crazy how fast he's hitting all the milestones!