Hey buddy, I just wrote you a really long reply that took me about 30 minutes to write because I know what it feels like to be in your shoes. But the server timed out... I'll try to give you a quick rundown of what I wrote.
-Cardio workouts are a must (running, walking, biking, etc.) You said you like gaming, but you have to get off the couch a bit

Try to get about 10-15 minutes of exercise for every 30 minutes you're on the couch.
-I don't know if you have access to weights or a gym, but that will only help you lose weight, if you don't try some push-ups and dips (see google for technique) and sit-ups.
-If you like to snack, have a big glass of water before you eat, it'll fill you up and a lot of the time, when you feel hungry you're really thirsty. Avoid sodas as much as possible, they're basically liquid fat, same with potato chips.
-Take it slow and be patient, don't overdo the exercise or the dieting or you won't stick with it, also, the faster you lose it, the more likely you are to put it back on. Be patient as well, you are not going to see results right away, but keep at it and its amazing how fast your body will change.
-Try not to let jerks at school get to you, they're going to be the ones pumping gas when they grow up, so don't let them get to you.
By the way, I'm Dave and I'm 21, I really hope this helps you, and good luck on your weight loss!! If you have any more questions I'd be more than happy to help. You can email me if you want
davtothec@hotmail.com