How Can I Confirm The Date Of Conception Based On Irregular Periods And Unprotected Sex?

Hi Doctor I had an implant from September to November 11 I had to remove it because of irregular period and spotting. On the 13th November, 15th and 25th I had unprotected sex, found out I’m pregnant on the 9th of December I was 1-2 weeks pregnant. Between the 3 dates which one do you think you it’s the day I fell pregnant since my period were irregular. My estimated Due date is 21 August 2022.