The most important thing to learn is data structures, algorithms, complexity.

The languages and techniques are not that important and change all the time.

Just go into a course where you understand what a hash table is, what is a NP problem, what is a turing machine, etc.

Understand what an operating system is, what is virtual memory, how a program is scheduled.

See how a compiler works.

Learn with a functional programming language, learn a language where you need to manage memory and pointers yourself, learn an "object oriented language".

This will help you all your life.