Traveling Merchant in the Apocalypse

One day a floating screen suddenly showed up for me. What? Traveling merchant? Trading? Farming? Armor? What do you mean by the fall of humanity? Can’t you stick with one genre? I just wanted to graduate!

English isn't my native language, so let me know if there's anything that seems strange when I write it in English, so I can try to adapt.

If you can, please give me your feedback too.

For now, I'm not sure about everything in this story, just there is a system, a female protagonist, an apocalypse and a bit of progression (weak to strong), I'm unsure if I should mark it 'cause the system will help a bit too, but I marked.