If you have had a normal delivery and your gynac or exercise consultant has checked you for diastasis recti then you can start at about two months. But as rightly said listen to your body.

Hi. I suggest wait 5- 6 months but you can start going on walks. Pls listen to your body and rest. <font color ="#3b5998"><b><a href="http://app.babychakra.com/article/1574">6 Exercises to Shed The Postpartum Weight</a></b></font> is a good read