KHAMMI21 - you are already at a healthy weight, so you aren't likely to lose much and if you do, it will take longer because you are already at a healthy weight. Your cousin is actually borderline underweight for her height, which isn't something you should aim for at all. I would recommend focusing less on the scale and focusing more on making sure you are following healthy habits (eating the proper nutrition - meeting your calorie and nutrient needs, doing both cardio and strength training, drinking water, etc). With doing that, your body will be healthy and take its proper shape. Just as I previously posted, your body is developing into a woman's body, which means you are going to have more curves and fat in some areas, which is a good thing. It is not realistic to expect to keep your child-like body as you grow and develop.
With you talking about depression, I strongly encourage you to speak to your parents and even a health professional about how you are feeling so they can properly help you with this.
I would also recommend reviewing this article: teens.sparkpeople.com/resource/wellness_ar