preterm baby weight is 1. 6 kg when born ..now at 6 n half month weight is 6kg ..when baby will start sit up and crawling?

A. Very good weight gain your child has so I would just say the child should be made said by completing the age of six months by the age of eight month they learn to sit with a premature child it could be 9 to 9 1/2 months and by then the child would learn to sit independently then the crawling will come into picture from the age 9 to 11 months