Worried my due date is wrong.

Lea
Me and my SO were quite certain we conceived on Valentine's Day but my doctor insists from the beginning that that it was 2 weeks afterwards. The last 2 ultrasounds I have had, she has been measuring 2-3 weeks ahead. I need to have a c section again as I had a lot of complications with my first child, and he has me scheduled at 39 weeks, a week early for his due date for me but a week late for what I believe is my actual due date. I don't want to be going into labor before my scheduled c section but it doesn't seem like he will listen to me at this point. Should I find a new doctor? Or try one more time to talk to him about my concerns. I just worry he's going to change his mind last minute and realize I need my section like 3 weeks earlier and that would be the end of October which leaves me very little time to prepare. Anyone else going through something similar?