Welcome to Android Forums, Bashbee!
I'm a little confused. Your subject, "
How to become a legit developer," implies that you're interested in becoming an app developer. But then you say, "
I just want to be able to understand and use the developer settings in my phone." Do you mean Developer Options in System Settings? Or do you actually want to develop apps?
Uh-oh! We have many old geezers here--myself included--who are far from the stereotypical tech-clueless older person. In fact, we have varying decades of experience with things like Linux programming. Don't assume that 55+ equals clueless.
Mostly by trial and error, a lot of reading, and having the desire to learn. So plunge in! When you're stuck on something or don't understand a response, just ask. No one here looks down on beginners. After all, we were
all beginners at one time.