You'll have to try different approaches and find what works, what does not work, so on. Shouldn't be too hard of a sell, really, given the way these kids today get excited about technology at that age. There's gotta be TONS of software that they'll learn from and like at the same time.
I must say, you landed a lovely position! If you wanna trade jobs some day, let me know (teaching convicted felons in a prison). No, actually I like it. But your position sounds very fresh!