I thought it was all to do with Pelvis too?

I am 5ft 2 and 48kg (sz 6) and have vaginally birthed 3 children (no insides falling out).
My mother is smaller and had 6kids.

One of my boys was nearly 9lbs

I looked absolutely huge my last two pregnancy's and people would look at my like
Sounds like a scare tactic to me without knowing all the facts.