I already wanted to write a book when I was about 10 years old. Video games, mangas, anime, and The Lord of the Rings were my main inspirations at the time, so I remember writing a story about a chosen hero in a fantasy world full of magic and mythical beasts.
As you might tell from the description, I wasn't very creative. I was telling someone else's story, because I had yet to live anything worth telling.
After a few pages, I stopped. I had no idea how to convey the feelings I wanted to convey or the acts of the protagonist in a compelling way, so I eventually got bored. I distinctly remember spending more time drawing maps, family trees, swords, and characters than doing actual writing.
World building was probably more enjoyable than putting words on a piece of paper. The idea of writing a book is probably more attractive than the act of writing itself.
It took me another 14 years to find beauty in the process and think of a more personal book to create, but there are still so many things I need to learn and do before I can publish a body of work with some value. Almost there.