Measurements greater than dates ultrasound?😳

Throughout my whole pregnancy I’ve always measured right on track...until yesterday. I was told I’m now measuring 4.5 weeks ahead.🤦‍♀️ I don’t have GD, and didn’t gain a lot of weight so my doctor ordered a ultrasound to measure Baby. Obviously I know ultrasounds aren’t 100% accurate and can be off by quite a bit. But I was wondering if the ultrasound shows baby is larger, will my scheduled c-section date be moved? Any other mommy’s had their dates changed this late? I’m 32 weeks btw.