It's important that you keep your program enjoyable, not only in the exercising and dieting, but that you don't expect too much too soon. Don't rely on the scale at all in the beginning, your weight will flucuate and that will throw your thinking off. You need to get more protein in your diet and good fats. Your at a great age to start towards a life long pursuit of health and happiness. Just keep learning more about dieting and if your cardio gets stale, change it up ( weight lifting is a great choice). And keep in mind all the benefits this will give you, beyond weight loss, you'll sleep better, have better energy, concentration, moods, breathing, strength, endurance and a whole long list of betters so just stick to it and give it time, it will be one of the greatest things you've ever done in your life!