Mathias is probably right that you'll fail, but so what? Just try man, then maybe you'll succeed eventually. On the subject of games, people often say start with a small project, but I disagree. I say just follow your vision, whatever it is. If it is too ambitious then that will become apparent sooner or later, and you'll have learned a lot about the feasibility of projects, plus whatever skills you picked up trying. If it isn't too ambitious, then you may just finish the project! Better to fail at something you want then succeed at something you don't want, in my opinion.
Also, it is hard to develop a skill (though probably more efficient) if you're focusing on developing it. It is way easier to get good at something if the learning is just a result of working towards your overall goal, just something you have to do to keep moving. That's why I say just go for your project you're excited about, cloning other games will teach you a lot but to be honest it's boring.
You seem pretty excited about this, so what's the hold up? Not like if it doesn't work out then the idea is ruined forever. Quit over thinking it.