This.
I started learning ue4 and 3d art around 4 years ago by doing just that. I then decided to go and get a formal education in game design/art/programming, so I did a diploma in screen and media specializing in game art, an advanced diploma in digital and interactive games, and a degree in media that has an entire subset of subjects in game art and game creation. just from my own learning from the docs/epic tuts/amazing people on these forums and anything I could scrounge around from the internet and mess around with, I’ve always been way ahead of the rest of my class and gave my lecturers headaches trying to get them to understand the things I’ve done for my projects.
don’t be afraid to break things, it’s the best way to learn.