3kg with one hand is too light, so it is estimated that you need to practice your appearance. I know a buddy about your height, and it's easy to do it with one hand 10kg. I suggest you change your mind. Fitness has a certain effect on fighting or self-defense, but it depends on who your opponent is. After all, these are all bad policies. In case of danger, running away is the best policy. As the fire demon said, martial arts are invincible in the world.