Why game developing is too hard? even when i do a tutorial from YouTube? (Note: I use Godot 4)
Because computers are complex machines and games use a wide array of their abilities. Games are some of the most complex software in the world.
Learning how to develop any kind of software takes time and effort - games, doubly so.
Personally, I would recommend you grab some books (ideally, ones from 2023 or earlier as the game-making book market is flooded with AI slop these days) about Godot, and possibly on programming on general because gamemaking books tend to gloss over the basics. Really work through these books, type in the example code yourself and mess around with it. That's the only way to gain a structured understanding and the ability to actually do things, in my experience. A tutorial from YouTube cannot give you that.
I don't really agree that books are the best way to learn game development. Reading game development books is kinda the same thing as watching a playlist, except it is more boring. You will still get confused, you will still struggle to do stuff other than what the book is asking, you might need to pay another book... (and I don't recommend you to pay to learn to make games). You do need tutorials to even get to know what the hell you're doing but in game development (and pretty much everything related to art in some way), the best way to learn is by doing. Make small games and focus on finishing them, try different things, do whatever passes in your mind and if it is fun, keep it. And most importantly: focus a lot on marketing, otherwise no one will play your games lol
I think a lot of people grab some books and watch some tutorials and they try to go it alone. There's nothing wrong with this and many of them even succeed with the effort of their own grit, but in my personal opinion I think having a teacher is the best possible resource you can have.
Someone to go back and forth with, someone to question, someone to explore and explain your ideas to who can better help you realize them. I'm suggesting find someone online, could be a friend, a mutual, or maybe go into development servers and try to find someone. Start small but build rapport. It's very useful to have someone who truly understands game design, and coding itself, in your corner. I can say with confidence that it helped me so I think it might help you too. Also if you're still in school see if they offer any classes in computer sciences.