My first ever story, yeesh. How old was I when I first started writing? Maybe 14?
iirc, my first story I wrote was called "Angel of Darkness". Which was about a young man who, when he was younger, accidentally killed a girl whose body was left in a construction zone cause I don't remember why.
Then he grew to be an adult that had strange occurrences in his life, frequent nightmares and seeing things.
Eventually he found he was being haunted by the girl he killed. The nightmares served as a warning of things to come and he had to avoid it somehow.
I don't remember much from this story since it was written so long ago, but, it never reached a true ending.