If you attempt to write that way, you create problems because you, the story's narrator, are not the first person. You create a character and see life and events through that person, but you're writing fiction, not nonfiction.
If you try it, the tendency will be to stay close to the facts and thus limit the scope of the book. The book tends to have a kind of wooden tone because you operate only with facts.
As one agent said, "You're too close to the scene of the crime and you have no perspective." She meant that trying to make your experience into fiction tends to take away the spontaneity and imaginative flow.
The worst defense you can offer for trying first-person fiction based on reality is, "But it really happened." So what?
It's not whether it happened, but whether it's believable. As the adage goes, "Truth is stranger than fiction." When you chose fiction, you cut away the lines that kept you tied to literal truth. Your responsibility is to provide a good read—an entertaining, imaginative story.
The worst defense for a bad novel is
"But it really happened."