Which Duane do you mean? Because not all of her stuff would be categorized as YA even if she was publishing it all for the first time today.

You can tell because some of it she is publishing for the first time today--this year, at least--and it's still not YA.

Even with today's supposedly more open YA climate, any novel which inspires matociquala and carbonel to shout, "What are you doooooing?" "We're fuuuuucking!" at a convention is unlikely to be published as YA. Handy rule of thumb, that.