The old adage for writers seems to be write what you know. There’s nothing inherently wrong with that advice. It’s a good place to start but that’s exactly what it is. A start. When you move beyond what you know into what you want to know is when things get interesting. It’s not like anyone has ever fought a dragon before (unless you’re Sharon Stone’s ex-husband, and by fight, I mean get one-upped by a lizard) but that’s never stopped people from writing about it.
For me, what I’m familiar with is the way disease can erode a person’s life. My mother was diagnosed with progressive-relapsing Multiple Sclerosis before I was born and I’ve shared her with that disease for decades. Since I was a kid, I’ve been fascinated with the way the central nervous system works (and doesn’t work) in the human body; the way science is still learning about the human brain’s reach and how easily it can be damaged.
Growing up, I devoured comic books, scifi/fantasy novels, TV shows, and movies. I got teased at school for not liking typical girly things but my way of coping with things I couldn’t control was to stubbornly stick with what I liked. I found escape from an invisible, encroaching enemy in other people’s stories, which kick-started my own desire to write.