I mean even if I am just average, I still have the duty to protect the world as I am living in this world after all. If it gets destroyed, I would have nowhere else to live anymore. And I know how horrible it would feel if I lost everything just like that. So I better stop those demons before it gets worse.
Plus, I know how to use a sword even if it's not that great, or so I think. I've trained myself to be able to wield a weapon whenever necessary. It's better than nothing at all. At least I know how to protect myself, especially if I am surrounded by enemies.
At least I can try my luck there. As I'm sure I would be needing that luck a lot.
And besides, I need to prove myself to everyone. For now, I have to focus on the present. My priority is to defeat the enemy first. Then I will worry about my future afterward.