I am learning the language c. After c I will probably move onto objective c and develop some iPhone applications. Then I was thinking about learning c# and xna. 

How long do you guys think it will take before I can develop a pretty decent hitting or roleplay game for the xbox?

My friend is also learning game design s I will have a game designer and my other friend is going to learn code like me. 

How long do you guys think it will take before we can develop a game like I said . 

Any tips on books or? What kind of game engine we hould use? Anything at all so we can stratup and learn that you know of.