Tangentially, it reminds me that probably the best book I ever I read, taken in the context of the time/mathematical ability in my life, was The Annotated Turing (Charles Petzold) - a sort of walk-through of and background to Turing's On Computable Numbers with an Application to the Entscheidungsproblem. It's surely the most 'sci' of any 'pop sci' I'm aware of, taking the reader through the actual paper but just really explaining it all step by step at a level comprehensible to someone without or before any undergrad CS or mathematics.

I'd thoroughly recommend it to (or as a gift for) any CS-interested teenager in your life.