If you like it and can afford to study it, then it’s worth it.
I have been “a mechanic” all my life. I’ve been working on cars since I was a little kid. I have only rarely done it for money, so I don’t consider myself a “real mechanic”- and as I’ve aged I have become less tolerant of contorting myself into tight spaces, lying on concrete in the rain, skinning my knuckles, becoming covered in toxic fluids, and other stuff you wind up doing when you work on cars without a real shop and proper tools.
In many areas, it’s hard to get a job as a mechanic without some ASE certifications and/or manufacturer certifications. These can be expensive and time-consuming to obtain. If you don’t work for someone else as a mechanic, then you will need to get your own shop and tools. This can cost a lot of money, depending on how deep into it you go.
The work itself can be satisfying. It can also be physically demanding and even dangerous. It’s very important to be careful- cars have lots of parts that can be immediately lethal if you screw up badly enough.
You can make pretty good money as a mechanic, but you won’t ever get rich doing it unless you screw over your customers. Don’t be tempted to do that- small operators can’t get away with it. Also, you don’t want to be that guy.
If you intend to work as a mechanic over the next 20 years or so, learn about electric traction drives. Learn about AC electricity. Lots of cars have electric drive systems these days, and the number will increase (probably for at least the next 5 years.) You might not ever need to work on these systems, but if you are going to work on cars you will need to learn how to be safe around these systems and high-voltage electricity in general.
The more stuff you learn, the more you can do yourself and the less you will need to farm out to the big shops. I don’t know CANBUS well at all, and I don’t have the requisite electronics to interface with most car computers, so I can’t do any of that kind of work (for example). Cars become more computerized over time, not less, so my knowledge becomes increasingly obsolete. I don’t like working on cars anymore anyway, so I don’t care particularly- but you will.