Good that you have passion that is most definitely needed in the branch of creative work. In that case, I suggest that you DO NOT GIVE UP the thought. Rather I suggest that you further build up the idea, the world, the setting and so on until you have the means/skills/connections to make it a reality. MMOs are complex projects that have a team of talented people behind them. I don't want you to be discouraged because of what I have said. Rather, take it as a cue to dig into game design and get your hands dirty with whatever makes in interested.
The best thing you can do if you want to be a game designer is to start small and NEVER give up a great idea. I've had an idea of a world and a game for 5 years now. Been writing the story and lore for a long time but because I feel it is such a great concept, I have not let it go.