TL;DR: make games you love, be aware of your capabilities, push yourself.Ah yes, to be 17 again... (It's when I started to have this same problem, and I still have it now, but to a lesser degree).
The problem was that I wanted to make games I really couldn't do because of insufficient (game) programming knowledge.
Over the course of few years I've been developing complex games (about a dozen). I've never finished a single one. For me it ended because of my poor design skills. All my games ended up in spaghetti code.
I've learned quite a lot (mostly frameworks, libraries and technical stuff about gamedev) because of attempting complex games, but I never finished anything.
So, when I was 20 years old I got back into gamedev. But this time I started with the easy games: pong, tetris and similar clones.
By then I've realized I'm just not that into gaming anymore. I was more into algorithms and science-ish software development.
When I was 25, I went back into gamedev. This time I've set some ground rules for myself:
- Start with a simple game which you know you can develop quickly
- Develop increasingly complex games (technical or/and design-wise)
- The next game may have at most one new difficult problem, you will need to solve
- Each game must at least attempt at being innovative
- Your may ONLY start on a new game, when you've FINISHED your current game!
These rules try to motivate & guide you, but not restrict you too much. For instance, you'll notice that I haven't defined what a "finished" game is. Some things are left up to you.
I'm now 26 and I've finished three games. One text game, one simple 2D tile-based game and one multiplayer (turn-based) 2D tile-based game.
Note that they aren't really impressive compared to what's out there. But I have to say that the joy of finally finishing and publishing a game or product to public is really, really inspiring.
I've had some ideas and partial designs for my next game, however I haven't started on development yet. That's because the rules guide me into making games that I will find worthwhile and ultimately finish.