Ultrasound measures vs LMP (When is my due date?)

So I keep reading posts people saying that the ultrasound measurements are not accurate, so I just want share my “due dates” to see what you guys think:

1st day of my LMP was March 11... my cycles are an average of 30 days... so with information I would be 37w 4d and my due date would be Dec 18

When I went to my first ultrasound, they said my due date was Dec 30 (I have been going by this date my whole pregnancy)

Now, since week 30, I have had 2 more ultrasounds and they both said that the baby is measuring 2 weeks ahead (which would put me around Dec 18)... my fundal height is also measuring 2+ weeks ahead

So is my due date Dec 30 or Dec 18???