Personally, I do not believe that your best fit is at defensive end. Based on your height, I believe that the best fit for you is at strong safety. You have the ideal height for a high school freshman strong safety.
My best advice for you is to work hard and perform very well in practice every day. In addition, what you need to do this summer (and every offseason) is eat healthy, exercise by doing weight lifting, and either jogging or going for a long run every day. If you do these things, you will get faster, stronger, and into better shape, which will greatly improve your chances of becoming a successful, top notch strong safety in high school football, who could go on to play college football in the future.