Wait a MMO for a first game? You're joking right?
I don't wanna sound like an arse or anything, but seriously start with something simpler. Diving into something that complex is just asking for it to be perma-shelved rather than finished.
I'm not saying ditch the idea, keep whatever idea you have, and while you're working on other stuff develop the idea (the idea, not the game itself).
Since I saw you say 3D the 1st thing you should do is get to grips with making 3D games, you need to be able to optimise the shit outa stuff etc. Then work on something that has netplay. Maybe do both a few times, improve on what you did the last time. Then go for the MMO.
They're a lot more complex than you'd think, even from a networking perspective they're incredibly difficult to get right.