Measuring ahead!

I had an ultrasound yesterday at 10 + 5 the baby is measuring 11 +5. The ultrasound tech thinks I'm actually a week further along because of how big baby is and how it looked on the ultrasound. But the dr is keeping my due date the same because of when I ovulated and when my period was. I compared it to my daughters 10 +4 ultrasound and there is a big difference in development. So if the baby is measuring an entire week ahead then am I actually a week further? I have small babies so I really can't see this baby being a big baby at birth. What do you think? It's really not that big of a deal about the due date but I kind of want to know how far along I am. Lol