My doctors educated due date for me is set for September 9th because I don't remember the exact date…

My doctors educated due date for me is set for September 9th because I don't remember the exact date of my last menstruation , but according to today's sonogram and the baby's size and measurements it shows that I'm 31 weeks & 4 days today , I'm gonna address this to my OBGYN next time I see him to see if they will be changing my delivery date cause I think my baby boy will be coming September 7th which is 2 days ahead 😆😄😀😜😎