Should i do Kickboxing, Karate or Judo.?

I suggest you do kickboxing. It is a great stand-up martial art. You will become flexible as well. It has a great arsenal of attacking techniques as well. But don't stop at just 1 art. Keep expanding, when your done with 1 art, do another. Example: Kickboxing/Karate and Judo. This is a good combination because you will have a great stand-up martial art and have one that requires throwing techniques. Best of luck with your martial arts career, and good thinking for taking martial arts at an early age.