Belly Growth

Disclaimer: I've never been pregnant, but research shows a lot.
I see women under 10 weeks "saying" they have their belly bump. With pictures and it's not just a bump it's pretty big for that early on. I understand everyone is different. But a lot of it is bloating and fat from before they were even pregnant. 
I am more so curious if I'm alone on this or do many women actually immediately have a bump? 
Also, on the fat part and gaining weight QuickLy instead of actually growing. Many women are like oh I'm eating from mot two. There is actually a chart of how much more you should eat each trimester also your doctor will tell you how much is healthy to gain.