Take a look at this: https://cylabacademy.org/learners.html#learning-paths
It's built to train people in the basics of cybersecurity. They apparently have resources that are aimed at middle-schoolers and high-schoolers but I'm not very familiar with those, you'll have to dig around.
You'll see references to "CTF". That means "Capture the Flag" which is a type of hacker game/competition/exercise.