Great. Learn how to read disassembly, grab ollydbg and ida+hex rays, if the exe is packed try to find an unpacked/dumped version. If not, lucky you.
Make sure you know how pointers work, you'll need them.
Have fun.
P.S. I suggest you familiarize yourself with reversing on a more simple game, like AssaultCube, seeing as the source is available it'll help you get a better understanding of what stuff looks like when it's compiled. Also I have a tutorial series on assaultcube. Should be linked to somewhere in the stickies, if not look thought my started thread