Reddit mentions of 13: Thirteen Stories That Capture the Agony and Ecstasy of Being Thirteen

I think it's this

Amazon link here

Congratulations. You've scored a job I would adore!

My suggestions:

• Dewey: The small-town library cat who touched the world.
  
• Jack London's Call of the Wild.
  
• Warm Bodies: A novel.
  
• 13: Thirteen Stories That Capture the Agony and Ecstasy of Being Thirteen.
  
• Romiette and Julio.
  
• Who Am I Without Him?
  
  Others have already mentioned my other choices (e.g. Of Mice and Men). And for a little non-fiction that might help them visualise some of life's big questions, try Stephen Law's "The Philosophy Files". I've gifted it to a number of teens in the past of all different abilities and have yet to hear criticism of it. "Philosophy Rocks" is another one of his that is also pretty good.