Yes, I highly encourage you to join your high school football team this season. It will still not (yet) be too late for you to start playing football.
Based on your height and weight, I believe that the best fit for you is at free safety. For your age, you have the ideal size for a high school free 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 free safety in high school football, who could go on to play college football.
By the way, your chances of playing college football depend on your performance in football during your sophomore, junior, and especially senior, years of high school. If you perform very well in football during your final 3 years of high school, you will greatly improve your chances of getting recruited to play for a college football program in the future.