As a beginner, it's hard to get to a point where you are confident enough in your programming abilities. While learning to code, you might also be confused at where does JavaScript end, and where Node.js begins, and vice versa.

What is recommended to learn before diving deep with Node.js?
Lexical Structure
Expressions
Data Types
Classes
Variables
Functions
this operator
Arrow Functions
Loops
Scopes
Arrays
Template Literals
Strict Mode
ECMAScript 2015 (ES6) and beyond
With those concepts in mind, you are well on your road to become a proficient JavaScript developer, in both the browser and in Node.js.

Asynchronous Programming
The following concepts are also key to understand asynchronous programming, which is one of the fundamental parts of Node.js:

Asynchronous programming and callbacks
Timers
Promises
Async and Await
Closures
The Event Loop