The best get fit quick scheme is a comfortable lifestyle change. Metabolism is only partially controlled by genetics, and easily enough changed by a smart diet and exercise. If you try anything too different you will become overwhelmed and fail. Instead just start valuing nutritional benefit over taste and your taste will follow. Making workout pacts with a friend or parent can also help you keep a decent workout routine. Running is the best method for losing weight but I suggest core exercises as well. Don't try to starve yourself, and don't expect immediate results. I bet you will be surprised in 3 weeks if you stick to something though.
"Dieting" isn't really good for anyone. A healthy way of eating regularly is.
When I was younger (teenage years), I went up and down with my weight. I don't like the words "diet", especially for your young age. At the age of 27, I realized the best way for me to be happy with my size (whether a few pounds extra than I'd like) is to except myself and be happy at my size. I needed to work on my insecurities and when I felt good about my self (the core of me) weight started coming off, I was more outgoing and wasn't bothered by others perception of me and I was confidant in myself. What I'm saying is embrace your weight of where you currently are (even if you'd like to work on a smaller you) and love yourself. Have small goals for yourself, try eating healthier and exercise. It's all about reading labels, based on your body type how many carbs/sugars should be consumed yet try not to let your weight be your prime focus. Remember magazines are deceiving, stars are photo shopped and some of their curves are cut out (digitally) and friends who may be smaller may have higher metabolism or different body structure. Best of luck to you!!