Here's some valuable tips:
1.) Obviously the foundation for a healthy body is a healthy diet. When at the supermarket stay out of the middle (where all the processed fatty foods are). Eat meats, vegetables, and lay off too much grains.
2.) You don't need the gym to start off. The best exercises you can do for your body use your own body weight (aka situps, pullups, push-ups etc...)
3.) LIFE CHOICES . If you even question whether or not something is detrimental to your health, it probably is. Lay off of anything that will interfere with your desired results.
4.) RUNNING! Get that cardio up! There is no set distance you need to run, start off with a mile, then gradually work up.
5.) Your results will come quicker depending on the amount of effort you put into it. You only get out as much as you put in. Take this at your own pace and build up. (NObody's ever built a house starting at the roof!!!)
BEST OF LUCK, I know you'll do great.