FTM anxious about baby weight

I’m a FTM who has been naturally slim my whole life (5’6” 110 lbs). I have a very narrow torso and very narrow hips. My OB once commented that I have a “small uterus.” Both my sibling and I were 7 lb babies and my niblings were 6-7 lbs.

The issue is that big babies run in my husband’s family. He and his brothers and his niblings were all in the 10-12(!) lb range. They also have larger than average heads. Like measuring in the 99th percentile for head size and wearing 2-year old hats at just a few months old.

Every appointment we’ve had so far, they’ve told me I’m measuring 6 days ahead (85th percentile). I just started second trimester. I’m scared I’ll need to have a C-section, that my baby will look giant compared to me and I’ll have trouble lifting it. My husband seems to think I’m overreacting but I think he has a skewed sense of what’s considered average by virtue of his family, and doesn’t see that I’m below average for most women in terms of width and weight. From what I’ve read, birth weight is largely determined by the father.

Does anyone have any advice or anecdotal experience with this to help allay my fears?