Some great advice. I would add that you are at an age now where you should engage is a regular physical fitness regimen. It does not need to be elaborate, just regular. Push-ups, pull-ups, sit-ups and running will give you everything you need.
While a sound education in unarmed combat is important, having the necessary strength and stamina are critical to winning a confrontation. A regular fitness program will not only put power in your strikes and give you the endurance to stay in a fight, it will help prevent injury and promote self-confidence. Being confident in yourself and your abilities not only helps you win the fight, it prevents one from starting.
Looking back, if there is one thing about my life that I would change, I would have started exercising sooner.