If you didn't unlock it already, I think you have to do well at the bookstore. I'm not sure if you have to fail in joining the competition, but that's how I got it.
Hi, sorry it took us so long to reply! Ewan already got it right but just to confirm, the competition does get prioritized so if you want the You Own achievement make sure you don't win it.
Thanks for playing and we hope you got that achievement! <3