Everyone's different it seems - With #1 I looked like I had a maccas belly (and I may well have had, I ate cheeseburgers like nothing else!) until about 21 weeks when I sort of started to steadily grow out.
My bub was posterior, so snuggled up against my spine, which might have played a part too.

Enjoy it, really - with #2 my stomach muscles didn't have the inclination for resistance and I started popping noticeably much earlier!