Anatomy scan

So, we had our anatomy scan yesterday at 20+4 weeks. The tech said we're measuring about a week ahead, but all the measurements I saw on the screen were putting us at about 22+1 weeks, and she also said that baby girl is measuring about 1 pound. This is my 4th baby and my other three were all a little over 8 lbs. But is this normal to be measuring so much bigger? Should i be concerned? I struggled with my three previous babies. Lol. She was also moving A LOT for a good chunk of the ultrasound...