When did you start measuring ahead in your pregnancy?

I've had big babies, my youngest was 9lb 13oz.

He weight more than my daughter who weight 9lb 6oz. The doctor suggested I have a C-section this time because she "expects" this baby to weight more than my youngest. But I am still measuring right on time and I'm 26wks.

I measured 3wks ahead with my other two, but I don't remember when I started measuring ahead. I guess I'm just worried about having a C-section 😬🥺