I have a general question about due dates.....

Ashley • PCOS, Gastric bypass RNY, 34 yearsold

I'm 5 weeks pregnant and my due date is August second. My surgeon says since I'm a lady who's had gastric bypass and we sometimes have small issues with pregnancy, I may be delivering before my due date..... in a nutshell, should I join a July 18 group or stick to and August 18 group?