Hello! Who has already given birth or who just knows how many ultrasou…

Hello! Who has already given birth or who just knows how many ultrasounds they have done, from all ultrasounds, the EDD was set from July 5th, 2021 to July 10th, 2021. And on the third screening at 31 weeks, they put it on June 19th, 2021?? The doctor says to orientate on the first ultrasound anyway. But somehow I don't feel calm about it, because many acquaintances gave birth exactly on the day in the third screening. But there is also no difference, of course, they had almost a 3 week shift like that. Can I really give birth earlier? Has anyone had such a