You should have the basic knowledge of HTTP methods, GET, POST, PUT and DELETE. Then of course Javascript is a must with the knowledge of async programming.

Node.js is javascript, so if you feel right with javascript you should be able to use it. You can find so many tutorial online etc. So I think the best bet it's just, open the text editor and play with. Create a simple api with it. Learn by doing :)

To begin with Node you should have some prior knowledge of one of the strongest & dominant language on the web i.e JAVASCRIPT !!

I come from PHP world, and I started working with NodeJS one and half years ago. Of course, you should first learn JavaScript as a language but you don't have to be master of it to work with NodeJS.

Main thing that helped me understand how NodeJS works is when I learned about event loop and single thread principle. When you work with PHP you don't have to think about that because either Apache or PHP fpm handles that for you, and in Node you have to think about it all the time. Good luck!