Great post and good insight. You are right on language choice although it can matter in one way. If you start off Imperative or Functional as they are different in mindset.

All languages in either camp have similar cores. The strongest similarities are in the C style languages. If you know any of these you can pick up the others real quick: C, C++, Java, C# or even swift.

What you will never be prepared for is real world code :)

The sort of code that is 10 years old and has had 10+ people through it each with different thoughts on the correct way to write things. All those quick and dirty bug fixes to make a problem go away :)