I was the same age as you when I started learning Linux but that was back in ‘95 so things have definitely changed since back then, especially for finding a job. There are some things that don’t change though so here’s my tips.

Learn UNIX, not Linux. Granted there’s a lot fewer Unix systems around these days but the core original concepts is still what drives Linux. If you understand the concepts and design patterns it will be easy to learn everything that runs on top.

Read man pages. All of them. ls /usr/share/man and start reading them. You won’t understand most of them right now but you will. Those nuggets of information you read and don’t understand will sit there dormant in your brain until you encounter something similar in the future and you’ll have some basic idea of how to figure out what to do. You’ll also learn many of the different, yet very similar patterns to how everything is designed.

Now that you know everything, do you want to realize how little you know? Try Linux from scratch. Build absolutely everything from the ground up to run on your specific hardware (bonus points if you have some new top of the line hardware to try and build stuff for).

Someone else mentioned having a second purpose for learning Linux. That’s good advice but I’ll put out another way. Linux is just a tool. Nobody studies and learns to use a hammer just so that they can use a hammer. They want to build stuff and in order to do that they need to be good at using a hammer. Linux is the hammer. Think of things you may want to create and use Linux to help you do that. Think of building things with raspberry pi’s, or hacking into some device you have that runs android so that you can customize it.

If you just focus on learning Linux you’re eventually going to hit a roadblock. That roadblock is that you need to learn to program. If you want to start the hard way (my preference), learn C. After that all other languages will be easy. Did you know that when they made the C programming language, they thought it was so easy to develop in that it would be used by the secretaries? You could of course start the other way with the easier language, like bash or Python. For me however that made it difficult to change languages or going up a higher level in language difficulties because I didn’t understand what was specific to the language I one, what was general software development, and what was the underlying system.

Another reason for learning to program is because that’s specifically what Linux is for and overall that’s UNIX is designed for. Going back to my earlier metaphors, if Linux is the hammer, programming is the nail (I think technically that’s probably reversed). There’s no reason to learn to hammer if you don’t have nails.

And the final reason to learn to program: it pays way more than being a Linux anon and there’s a lot more job opening

Some very old but incredibly insightful books: * The design of the UNIX operating system.