11.3cm but only 13 weeks?

Maris
I'm 13 weeks and at my sonogram the tech kept measuring nugget asking if I was actually only 13 weeks...isn't 11.3cm too big for only 13 weeks? My original due date was December 23rd, but they bumped it more towards January 6th-13th. They're not giving me an exact date or anything, it's weird. They kept saying how it didn't "add up" with my due date being December 23rd, and nugget wasn't even measuring to have the due date of the 23rd anyways. But NOW, the little goober is OVER compensating in length 😂 just looking for advice!