I'm 4 months post c-section and the only reason I haven't begun running again is because I am breastfeeding and haven't found a supportive enough bra to handle the expansion of my chest. I think you should listen carefully to your body but if you start doing a slow shorter run and work your way up gradually and you aren't feeling any negative implications then you can exercise as soon as you want. Just don't over do it, thinking you'll be at the level you were at post surgery. Good luck, hope this helps and happy running!