My OB goes by the 12 week scan date, but BOTH of my girls came on my LMP EDD, so I don't bother with the scan date. Every baby is different, as is every Dr.
How exciting for you, a beautifully healthy little bubba playing around in there!
My entire pregnancy has been a date tug-o-war between midwives, doctors and sonographers. Fortunately, I landed a midwife who was quite happy to fight for MY date. She was away for my 40 week appt (!) but her stand-in said that they're more likely to use a 12 week scan EDD now than a 6 week scan EDD. Anyway, I won, and they're using my date.
I would go with your LMP date if that's what you trust.
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