Wrong due date??

Jackie • Hello! I`m 31 years old. I have a 7 year old son and a 3 year old daughter. My hubby and I are trying for our 3rd baby!
I had my first scan yesterday. Doctor said I'm 6 weeks 4 days with my due date being June 14. But this app says I'm 6 weeks 3 days. Could the doctor given me the wrong due date??