So you wanna build games for Windows? I once tried my hands on XNA framework and with just couple of days of training, I had a grasp on basic idea. But can I start creating video games with 20h of learning? I doubt it. If it is 2D, may be, just maybe. But I repeat, I heavily doubt it. Unless you already have experience in the underlying technology it is written, it needs lots of lots of hours of training before you even lift your finger to say, "Just start creating games!".
So I advise to you learn more and start creating items one by one. First of all sprites, logic, theme, game play all this during your learning phase and see how you can apply what you studied and see where it fits. This, I'm sure will reward you once you have a half-baked game which you are proud of.