I want to learn more about computer science. Where should I start?
This sounds like a better fit for say academia.stackexchange, as this is mostly subjective, so bear in mind this is mostly &quot;just my opinion&quot;.

My advice would be to start with Algorithms, at a high level: learning about the big algorithmic paradigms (greedy, dynamic, linear programming...), runtime analysis (all the landau notations and derivatives, amortised analysis...), and go through the sorting algorithms at least. A good resource for that could be [1]. This part should be seen as &quot;fun problem solving&quot; I reckon.
In parallel, I would study the foundations of computer science and computability (easier if you've studied Logic before):

Starting with finite automata/rational languages, and grammars
Building your way up to Turing Machines (with equivalency to recursive functions and lambda calculus)
Finally getting to the distinction between computable and undecidable

Along the way you should have got a small introduction to complexity theory, which should enable you to understand what the classes P and NP are, as well as what an NP-complete problem is.

[1] Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, and Clifford Stein. 2009. Introduction to Algorithms, Third Edition (3rd. ed.). The MIT Press.