I have a thread around SYW somewhere, with a short story (a Chapter One? still don't know). The story was originally the midpoint in what was going to be a memoir. At a point, the reason I was writing the memoir was no longer relevant, but this part was one of the better pieces of writing I've done (in my very humble opinion) because of how real it was.
So I changed some bits, then some more. And now it's a (maybe) Chapter One to a fantasy story. And if I'm saying so myself, and I am, it's still darn good. It's still 98% a true story.

So yes you can. It's your writing, you can do what you want. Find the parts that speak to you and start saying "What if instead of left, she went right?" or etc.