I'll start it up with my own.
The first story I ever created was a spur of the emotion.
Tragedy happened and I lost the closest thing I ever had to a best friend...who really got to know the real me.
Anyways, my sorrow turned into hatred, an intense desire for Humanity to just...go to hell. Of course, I was young and impulsive back then so I've gotten over it now.
Looking back though, I felt this sense of duty to restart the series over again.
I've matured a little so I felt it was time for me to revamp the story that started it all and make it a more memorable one.

Okay, your turn.

The first story I ever wrote was a Naruto fanfiction. It was very crappy, but it helped spur my passion for writing and my desire to learn the writing fundamentals.

Excluding any fanfiction, the other first story I wrote was a sappy love story between a slave girl and her master's son. It was just some experimenting with plot and writing techniques.

I finished my original story and lost the fanfiction, but I have no desire to revive them. Instead, I'm putting all my effort into my current/future projects. But it sounds like what you're doing is pretty cool and I wish you the best of luck with your series. :)

The first fiction piece that I ever wrote was a project that I had to do for school my Freshman year of high school. Mostly before that I did expository pieces; even having "worked" for the local paper for a school year.

It was about a world where it's against the law to have free thought, but this little girl did anyway. She was killed, but ended up becoming a martyr, sparking a revolution in the Big Brother-esque society that my characters lived in.

The project was a ten-page maximum, so I ended up having to cut about fifteen pages in order to submit it. It was the most satisfying A that I ever got. Now that I'm an adult, even though I suffer from a lot of insecurities about wanting to pursue a career in writing/journalism, I know it's what would make me happier than anything.