Well I ain't fat but I'm pushing 43 and stay pretty fit so I'll offer what has worked for me.
My diet is not great. I eat the burgers, pizza, meskin food, and drink 1 coke a day. The flip side is I work out on a regular basis and have done so since 16. I believe that has helped my metabolism. I think you are on the right track with cutting the sodas and I would also watch your sugar and fat intake.
I know crossfit is real popular but I really don't see it as being what an overweight person should start with. I see more a potential to injury.
I would concentrate on cardio stuff initially with some pilates or other stretching regimen and add in some simple muscle building exercises. After that I would look into some high intensity interval training exercises. Once you are at your desired weight you can reward yourself with eating some of the things you cut out, just don't over do it.
Good luck. My wife at 22 lost 40lbs. by walking and eating better. We both are now core building fanatics. I stopped doing heavy weight training when I started having back pain and haven't looked back and I am in better shape because of it.
There are no saints in the animal kingdom, only breakfast and dinner.