Two due dates?

I was thinking a lot about my due date today because it is getting SO CLOSE. I remembered that my actual due date of January 12th is kind of bogus. It may be TMI, but here's why I believe that due date is bogus:
Back in April we decided that we wanted to start trying for kids again. We tried initially in December and January but we were unsuccessful and it was a little disappointing. But we stopped trying for a while because it was a little discouraging. In April we decided to try again. Basically without any extra detail, the situation was such that we know the exact day I became pregnant, the exact day we conceived successfully.
So we got a midwife after we moved in April and we told her the situation was such that we know the exact day of conception. She agreed and based on that she gave me a due date of January 3rd. We know without a doubt that the day of conception was right, therefore January 3rd to me seems more correct. Then I got really sick and ended up being required to get an OB as well as my midwife. Then around week 13 or 14 I think they did a comprehensive ultrasound and they said that based on the size of the baby the due date was January 12th and they totally ignored me when I told them I knew the exact day of conception.
The thing is that due dates are just guesses anyway. But it will be interesting to see how things play out. I firmly believe that the January 3rd due date is more accurate. I think he will be born sometime between December 26th and January 3rd. Just according to my mama gut. No, I don't mean my actual gigantic belly :) I really have a strong feeling that he will be born around then.