Do You Really Want to be Doing this When You're 50? 14 years ago
I'm with you, I'm rounding 40 myself, and was not happy for the brief couple years of management.
When filling out a 'secret question' for some site, it ask what your ideal job would be. I didn't even blink, it was: developer.
Do I want to be doing this when I'm 50, hells yea.
If I had trillions of dollars, I would still code. It's who I am, it's what makes me happy. If you don't think you'll like development at 50, then you may have picked the wrong career.