Fetal age

Kerry

Hi everyone , so my first scan went perfect yesterday we have a heartbeat 🙌🏼🙌🏼 . Just a little confused so going by the first day of my last period I'm 6 weeks and 6 days however the tech said the fetal age is at 6 weeks and one day . Should I be going by the fetal age ?? Just so excited to hit the 12 week mark to tell people this is our first baby 😍