Calculating Due Date


My baby measured 4 days ahead at our 12 week US at 12w4d. I had an US at 7w6d and the baby measured 8w exactly so I’m not sure if they will consider changing my due date based on the measurements, especially since I have irregular periods? Has anyone had something similar? I don’t see my provider until I’m 15 weeks. The US tech told me they usually don’t change the due date unless it’s 7 or more days off but I didn’t tell her I have irregular periods so idk 😐