If you really want to do something here's what I suggest. Start out small, taking on a project as big as starcraft will be discouraging when you are stuck every step of the way. Another thing you have to look out for is copy rights, 90% of all the fan made games get shut down because of stupid copyright holders, who don't even plan on making a new game of the series yet still shut down anyone who tries to add to it (System shock 2 remake, monkey island games, and many more have been shut down). What I'd suggest doing is learning Adventure game studio, and making a game either solo or with a few dedicated people. Coordinating something with many people online just wont happen, people will get bored and quit.