my son still not rolling ( upside down )

A. Hai good evening !!Generally babies roll around 3-5 months some will take time also. If baby is gaining weight ,achieved milestone if social smile ,responding to sounds then dont worry yet there is 2-4 weeks time.. Do regular massage ,tummy time(place a blanket or mat on floor keep baby on tummy side for 5-10 minutes daily this tummy time helps in roll over,holding neck,crawling,abs strength.