Help please

Bryanna

I just went to my first ultrasound. 6-14-19 and they said by my last period I should be 6 weeks 5 days 6-14-19 but they measured my baby at 6 weeks 1 day. Now I should be 6 weeks and 3 days. Do I go by what they said or do I go by my last period? This app right now says 7 weeks. They kept my due date the same February 2nd 2020.