Los Alamos, NM
Once I hit 30, I began asking myself that question all over again. A few years later, I woke one day to realize that I simply didn't believe. For many reasons, I am a much happier (and more emotionally healthy) person having let go of god. There are still days that I wish god did exist. It would be a relief to relinquish responsibility to a greater power.
But, even better, I can see life for what it is, and work with reality. That's more powerful than any god could hope to be.