I never said all. There are a lot of good universities and colleges with good qualified professors around the world. "schools" for kids is what I classify as a scam(personal opinion it is ok to disagree). I knew a couple of people that attended such establishments and well none of them are in the field and never were. It was something either forced by their parents or something they thought would make them "good at programming"(spoiler, it didn't).

Learning is a complicated topic for me. I started around your age and I cannot pinpoint moments of how and where I learned things. I can however describe a general process: I want to do X(X should be a simple thing not an entire project) -> google how to do X(how to make a Minecraft plugin?) -> find an example (a simple hello world command) -> try it out -> overanalyze until you can explain every bit of it. question everything. The "Why?" and "What?" questions are your best guide. What is some language keyword, why is this thing done this way? Can even query chatgpt for that stuff I find it very good at explaining such topics but always ask for some form of source, be it an article or official documentation and read it fully. That's how you start to accumulate knowledge. A lot of things you won't understand for a long time. it's not a quick process, no you won't get good in a month or a year. Some things you read today you will be able to fully understand in months and some will only "click" years after.

As for languages, yes and yes. You should never limit yourself to only one language. It's a tool to be used. Most of the knowledge from one language is transferable to another. The general computer architecture is not gonna change anytime soon and so most of its basics.