Guys I'm super happy

Saleisha
I went to the doctor today and I'm currently 6Weeks & 4days pregnant, he also let me hear my baby heart beat it was super duper amazing omg‼️‼️❤️❤️❤️❤️, but what's puzzling to me is that he still can't tell my due date which is odd because he knows how far long I am so I'm just curious on how come he don't now my due date??