My baby is 9month.she didn't crawling yet now. otherwise she is normal and active. what is the reason?

A. hi dear Baby development varies. Crawling on hands and knees typically happens between the ages of 7 and 10 months, though some babies will start crawling later and others won't crawl on their hands and knees at all before they walk. There are several stages of crawling as well as styles of crawling.