Arduino boards are a great on ramp to computer hardware and programming. Hides a lot of the really hard stuff, and has tons of examples online for how to make it work.
Ben Eater is a guy who's started selling kits for building an 8 bit computer from discrete chips on a breadboard. A whole kit is $300, which is a bit steep for a teenager, but you can buy it and complete it in pieces as you're able.
I also think the suggestion about connecting them with like minded peers is an excellent one. A local FIRST robotics group or a makerspace would be excellent as far as making those connections goes.
Ben Eater is a guy who's started selling kits for building an 8 bit computer from discrete chips on a breadboard. A whole kit is $300, which is a bit steep for a teenager, but you can buy it and complete it in pieces as you're able.
I also think the suggestion about connecting them with like minded peers is an excellent one. A local FIRST robotics group or a makerspace would be excellent as far as making those connections goes.