Hi guys! Thanks for inviting us over.
For me, I do think of YA as a genre--but a genre made up of other genres. I particularly like the freedom of being able to take elements of, say, mystery and romance and fantasy and mix them up together or to write a book that goes in a different direction to my last one and feel confident readers will still be able to find it. Not that you can't do this in adult fiction, because of course you can--but there's more of a risk that your books will not be in the same section of the bookstore or library or where your readers can easily track them down. The only defining characteristic that I see is stories focusing on protagonists who are, well, young adults. Certainly, a sense of heightened immediacy that comes from first-time experiences is also often present, if not always.
I did make a conscious decision that I wanted to write YA, but it was because it's where my voice naturally wanted to go. In the early and mid-2000s, I started reading the new crop of modern YA authors and felt an immediate recognition. These were the kind of stories I wanted to tell. I have been working on my first thing for younger readers over the summer, and that was fun too--and a story that just fit middle grade better than YA. Maybe someday I'll write something for adults, but I have no idea what it would be or when.
I suppose there are some people who look down on YA authors -- or grubby genre authors, in general (*rolls eyes forever*) -- but I've been lucky enough not to run into many of them. And there's really nothing like hearing from a teen who has loved your book.