Priya Sood
Hello Anjana! Every child is different and will reach milestones such as sitting on their own, crawling etc at their own pace. Do mention your concern with your pediatrcian at your baby's check ups. As long as the Dr. says its ok there is no need to worry. Pls do check our informative articles.
Neha Agarwal
Don't worry every baby has their own growth milestones. As long as baby is within the range of development milestones, it is fine. A bit here and there is totally ok. Also do cosult your doctor for the growth of your baby. Here are a few articles that can be of help.
http://www.babychakra.com/learn/baby-development
Recommended Articles

Rithuparna Ravindra
we do place her on the floor many times every day in hope that she will learn to crawl but ends up losing hope.she seems even lazy to roll over.