I want to go back to work after delivering my child, but my mother in laws says I should stay home and take care of my child. I do agree with her that for a certain period of time I should be home with my child but when is an appropriate time to leave my child to go back to work?

It depends on yourself. Agreed that to you should take care of your new born baby during your maternity leave. But you may arrange to take care at night time when you starts to work after finished your maternity leave. If you have proper arrangement, believe that you will not miss out any of their early stage moments.