I don't want to lessen your motivation, but I would definitely not advise making an FPS or any RPG if you have never made a game before.
It is not very much fun to make games if you have to learn 2 years worth of computer science with your first game.
However, you can still learn to make games, and it is a lot of fun.
I would start with something small, yet powerful, so I recommend the LOVE2D engine.
It uses Lua, a powerful verbose language made in C, but is easy to gradually learn (you don't have to learn very many things to get rolling.)
With LOVE2D, you should be able to have a game ready in a matter of half an hour.
Once you learn Lua thouroughly, you will understand the concepts of programming, and will be ready to understand more advanced concepts.