Yeah, I used to think just like you. I wanted to be able to make a game. Then I would go "no! I want to make a web app!" then I will say "no! I want to master Unix!" And this entire cycle of "no I want this, no I want that" never ceased.
So here's a short answer to it all: stick to doing what's at your finger tips.
So here's a story
I always wanted to build programs in general. It didn't matter what; I just wanted to build something. In the the end, the best way that I managed to move on with my life was just try to do something by using one tool that I "hear" being talking about. If I failed entirely, I would move on to something else.
And that's how I got into game programming.
It all started with Visual C# Express being showcased on the Microsoft.com home page. The entire IDE was blatantly available right in front of me, so, I clicked the download link and got started on it right away. I watched video tutorials, wrote lots of code, and there, I was set.
It was then I started to go left and right to find something to do. I could've built a Windows Forms application, or I could've built a website. Then I would be thinking about feature that I could include within my projects, but I will never proceed to actually build something. I just wasn't motivated enough.
It wasn't until the MSDN news feed in Visual Studio announced the release of a free framework to bulid your game on. It was XNA Game Studio Express v1.0! I got started right away. I built a few small games here and there.
But here's the catch: I felt more motivated to work on a game that just popped into my head, than the ones that had to think really hard for. I had a great idea to build a 3d snake game, worked on it for two days straight -- while taking breaks of course -- and voila! A very handsome game that works!
And when it would come to those games where my sole intention was to impress my friends. I would work on it for two or three hours and give up, and never look at it again. In fact, I haven't looked at it for at least two years.
So here's the moral of the story: let inspiration guide you. Don't force yourself to do something. If you want to make a webapp, maybe you might want to consider solving a problem that always bothered you. If you want to make a game, then I suggest that you look at the small things in life that you found to be "fun." Again, it all comes down to inspiration.
I hope that helps.