Losing weight after baby and tummy fat?!?

So I had my baby boy over a year ago by c section I have lost a little weight but still have about 30 I would like to lose. Since I had a c section I have a little pooch lol and I hate it! I'm gonna start walking everyday and drink lots of water, if I start losing weight will my tummy go down or will I have to work that too? Will it get worse if I lose weight? It's not that bad. But I just don't like it. And I drink pop all day. If I just drink water will I lose a lot of weight? Thanks:)