Hi! I'm 12 weeks pregnant first time. I've had 2 dating scans that say my due date is dec.21. My last period was march 19. I want to know if these scan are right they match perfect with my last period. Y I'm asking is I was separated with my husband the month before I made a mistake and slept with someone feb27. My period was feb. 22 that month. I just wanna make sure that the scan is right and I'm not carrying a guy I don't even know baby.