Better to be big or small at the end pregnancy?

I know that whether the mom has a big or small bump means very little about the baby, but I'm just curious. At 38 weeks when I gave birth, I was pretty small still, but my sister in law is only at 30 weeks and HUGE and keeps rubbing it in my face. Do you think there is anything to her bragging that she is so big, bigger than I was when I gave birth? I'm curious what other women who were pretty big think.