IUI success- dating

Found out our 2nd IUI was successful!

But I have no idea how to calculate my EDD

My period started July 9, and we did really early monitoring and ended up triggering July 18, having the IUI July 20. So when I found out I was pregnant July 30 it was exactly 3 weeks.

Is calculating EDD from my period the best idea or should I consider myself 14 days from my ovulation, even though it was only 10 days?

Any ideas are helpful!