Macrocephaly

I just got back from my daughters 9 month appointment and the doctor wants her to get an ultrasound of her head. The diagnosis is Macrocephaly. She’s in the 90th percentile for head size and said this is going off of her curve. He said he’s not super concerned and most of the time it’s just because mom or dad have a big head, which be both do. But of course I’m worried sick and can’t stop crying. Has anyone else experienced this? What was the outcome?