It's good to recall the life and work of author Ray Bradbury (who died yesterday at the age of 91) when you fall into the but-I-only-write trap.
But I only write . . . science fiction. Fantasy. Westerns. Romance. Short stories. Poems. Mysteries. And on and on and on.
When it comes to writing, when it comes to your writing, there is no "I only."
Writing is writing. No matter the genre.
I highly suspect those who write so well in one form wish they could write as well in another. The mystery writer would like to pen a fantasy. The fantasy writer wishes she could do a literary novel. The literary novelist would dearly love it if as many people read his work as looked forward to the next children's book about a wizard boy in England.
Writing isn't a one-genre-fits-all talent. The gift you've been given, and are nurturing and strengthening, is uniquely your own, just as that developing (or developed) voice is.
10. He's never told himself he can't.
9. She isn't slowed down by concerns about punctuation, spelling, grammar or style.
8. He has a story he wants to tell.
7. She isn't hung up on what size a "real" novel has to be.
6. He has no doubt he can finish it.
5. She thinks it sounds kind of fun to do.
4. He's blissfully clueless about publishers, agents, and such.
3. She's read some novels.
2. He's not worried about what others will think of it.
1. Instead of doing a bunch of other stuff, she can choose to sit down and write!