my baby is 8 month 15 day old but she can't crawl by her self , she doesn't like to sleep on her stomach also.. and not trying to put step on her knee..

Question

Accepted Answer

sitting without support and crawling in children may sometimes come after one year of age also.
 if the growth of the child is proper no need to worry. just take care of regular diet and baby massage which will help in strengthening the musclesg needed for sitting and crawling. 
in some cases crawling may be absent in children and directly the child will begin to stand with support and later walk with support gand then without support.
take a medical check up done to confirm if there is need of any intervention.

Accepted Answer

At 6 months old, babies will rock back and forth on hands and knees. This is a building block to crawling. As the child rocks, he may start to crawl backward before moving forward. By 9 months old, babies typically creep and crawl.