Tad confused about due dates 🤦🏻‍♀️

So the due date I was given was the 26.01.2019 at 8 weeks, for fun I just calculated my due date from what my last period was and it told me my due date should be the 22.01.2019.

So I’m confused as to which is right even though they aren’t that far apart at all.

Also I was given a EDD of the 18.01.2019 because he was measuring ahead so which one is most accurate ?

I know the due date is just a guess but it’s getting so close now I’m starting to get impatient and excited !