Depends on whether or not I have the opportunity to prepare before actually coming into contact with my opponent.
If I do, I'll pick guns, find a vantage point suited to the specific gun I receive, set as many snares and noisemakers around it as the local vegetation and terrain allows, and camouflage myself in order to wait my opponent out. Few people have my patience, and only a small percentage of people on this planet have a clue how to deal with forests anymore.
If not, I'll pick melee. Statistically speaking I am likely to have a strength and/or agility advantage. In spite of that, I'm reluctant to go this route, mostly because weaponized hand to hand combat between people that don't know what they're doing, like me, is both dangerous and chaotic, and anyone used to fighting is likely to tear me apart, almost regardless of age and physical condition.