When I was in my late twenties, a friend suggested that, since I was an avid SF reader and had been since I was barely a teenager, that since it didn't look like the poetry was going where I wanted, I might try writing a science fiction story. I did, and the first story I ever wrote was 'The Great American Economy.'
I've often said that there's no one thing that I do or have done that is particularly unique. There have been a lot of other authors who were in the military. There have been a few others who were pilots. There have certainly been a lot of other people who were in politics or served congressional staffs.