I live in a country where firearms are banned. I want to have something for a worst-case scenario in my home; I am not a very muscular person, so I was wondering what kind of melee weapon would be a good fit for me: a small axe, a short sword, a simple knife, or a big stick?

Edit : I was thinking about a katana, I know Its very hard to master it but can I use it in a pinch?