Bump d'bump

Cassandra
So, I'm curious. I'm 19+4 and wasn't overweight per-say pre pregnancy and did a lot of running and weight training as well. Due 18th December so I don't really have a huge bump, in fact, a lot of people have said they wouldn't have thought I was pregnant. 
A friend of mine who was a lot slimmer than me and similar frame/height is due 2 weeks beforehand and she's got a huge bump!!
Been doing some research (totes getting #bumpenvy) and has anyone found that (she and I are both FTM) if you've stronger abs you tend to show later?
Be great to hear other FTM in similar situations!