[Ask JM] Considering building my own DB, very specialized, and idea

I am a lowly developer, used to to back end web development and network management, then the internet changed and everyone has their own little piece the dev pie and my brain can't keep up.

I have nn idea to make a database, a pure key value store, they key can be up to 63 characters, though possibly double that. The value can be up to 256 characteers. It will be redundant, load balanced, and able to return answers from anywhere in the world in fastest would be around 2ms, longest would be on average 40ms or so.

Bad idea, thought experiment, proof of concept?