I have a question for the mommies that have already delivered. About how long did it take for your…

I have a question for the mommies that have already delivered. About how long did it take for your baby bump to flatten back out? I tried to stay active and eat healthy most of my pregnancy so I ended up only gaining 28 pounds (I'm 39 weeks 4 days now). I ordered a postpartum waist trainer (the belly bandit). And I plan to start exercising and going back to a vegetarian diet as soon as I have Micah. I just don't really know what to expect.