I cut my teeth learning to work on supercharged jet skis. I messed up a lot of stuff, but got functional towards the end of that hobby.

When I got into cycling, I decided I wanted to learn to work on them as well. They are much less complicated than working on a supercharged jet ski. Really basic mechanical principles at work. If you have turned a wrench on anything mechanical in the past, then this will be easy.

Bikes do have very specific tools once you get past the basics. Unless you are opening a repair shop, you really only need the ones that apply to your bike(s). Might as well buy the good stuff when you need it.

When I would take my bike into the shop, I'd ask if I could watch and learn when they worked on it. Then I started watching GCN and similar videos online. Everything you really need to know is on YouTube/Google at this point. I invested in a bike stand and then started working on stuff as I went, asking questions here when I couldn't find the info online.

Now I've built a couple of bikes from the frame up and work on several friend's bikes for fun. I enjoy it. I find it fun to tweak my bikes until they are working as close to perfectly as possible. Improves my enjoyment of riding them as well. By far my favorite bike I've owned is the one I built.