My bloat started going down about 12 weeks, and I started to show a bit shortly after. It's all just organ displacement for now, helped along by my being overweight to begin with, but there's a definitely difference in photos of me sucking in at 8 weeks and sucking in at 12 weeks, despite my weight staying the same. It'll be awhile yet before the bump is actually full of baby, but that doesn't mean that it isn't baby's fault when you start looking pregnant.
Some women, though, take forever to show. My SIL was 20 weeks before she showed as much as I'm showing at 14 weeks. Everyone is different.