Based on your height and weight, as well as your good hands and 40-yard dash time, I believe that the best fit for you is at the wide receiver position. You have the ideal size for a high school freshman wide receiver. Keep in mind, some high school freshman wide receivers are shorter than 5 feet, and weigh less than 100 pounds. On defense, I believe that your best fit is at cornerback.
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 upcoming (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 high school football player, who could go on to play college football in the future.