OK, there are a lot of really bad answers on here. I have been a Computer Engineer for over 15 years now, so I think I can speak to what skills you need to learn in rough order of complexity:
- Math. Math is the language of Engineering. If you can’t speak the language at least a little you are hopeless.
- Physics/Fields & Waves / Thermodynamics. You need to understand at some level how the universe you intend to manipulate works.
- Circuit Analysis. Without understanding how electricity flows and works with various basic components you are nowhere.
- Digital logic. Learn to use transistors to build gates and flip-flops, then combine those gates and flip-flops to do useful things.
- Microprocessors. Take the useful parts from Digital Logic and start building general purpose processors. You don’t need to DO this, but you should understand the basics of how processors and memory are organized and used.