I would go with hand-to-hand. I'm 22 years old, thin, light, healthy, and fairly athletic. I have used guns only a few times in my life, and never with moving targets. As for why I wouldn't choose melee, I don't get to choose the weapon, and I've had some martial arts training, which gives me a slight advantage over an untrained opponent, as I have another weapon in my arsenal (so to speak) to use and a better idea of where to aim. It would be safer for me to go hand-to-hand than to risk hurting myself with a weapon I am untrained with. I would just have to be careful not to fall prey to ambush, and if the opponent is better trained than me, oh well, then I have to innovate more than usual and follow the same rule that all life on this planet follows: Adapt or Die. Outclassed is outclassed, and there wouldn't be much I could do about that regardless of the mode of combat besides innovate further.