How rare Is It to have a wrong due date? Long

Shauna • Levi Shine ⭐️ due 02.02.2018. Momma's world. Daddy's boy!

Please no rude comments just a question! A co/worker and I was on the subject about It. Which I believe the accuracy of what the doctor says Is true! So not me In general but... A family member of hers which Is now 30 weeks pregnant. Her doctors ultrasound tech gave her a ultrasound at the very beginning and one at the 20 weeks scan. Due date never changed. And she will not have another before the birth. So she’s a little upset she will not know the around the baby’s weight or how big he might right now. But everyone thinks she’s further along and the doctors wrong!! And believes he should do another ultrasound. Her dude date Is 2 months away but everyone thinks she will go Into labor within a month. Because her stomachs so high up and now It’s so low. And so on... Like I said I know this don’t mean anything and I know you should listen to the doctor just want opinions on It lol. Could this be possible? I know babies come early and what not. But being off on due date and actually being futher? Comment your thoughts. 😉