Insurance in Colorado

I'm not a Colorado attorney, and the laws differ from one state to another, but I suspect that, like most places, you have to get a state license to sell insurance.  You'll almost certainly have to tell the state about the conviction, on your application (and if you don't, they will probably find it anyway and you'll be denied the license for lying).  What the conviction was for, how long ago it happened, and what you've done with your life since then might all figure into the decision.  But if the conviction was for any sort of theft or dishonesty, I'd say you're probably a long shot at best.