I could not disagree more, refactoring is perfect for a newbie. It's not an advanced technique, it's fundamentals. Any beginner who can write a method can extract a method.
But more than that, refactoring provides the mental models and the vocabulary to talk about, reason about, and understand code. It provides well-worn expert advice about the characteristics that make good code good and bad code bad, heuristics to be able to recognize good and bad code, and basic techniques to transform bad good into good safely and effectively.
There may be some advanced techniques in the book itself which won't be useful to beginners, but that's true of any programming book, and that's easy enough to skip over and return to later (especially with the organization of the canonical refactoring book specifically).
A beginning programmer who has learned even the simplest of refactoring techniques (extract method, insert/remove cached value, etc.) will be able to look at a piece of code and see the ways it can be changed, and will also have a reasonable idea about which changes are more likely to improve the code. They will also have the mental models and vocabulary to talk about, reason about, and understand the code, even if only to themselves. These tools are hugely important for beginners. They can transform coding from a task filled with uncertainty, fear, and irregular advancement born from experimentation to a task filled with confidence, knowledge, and curiosity.
Certainly practice a lot, but don't just blindly stumble about on your own, there's lots of good material out there, learn the techniques and then practice applying them, build up your toolkit a bit at a time until you feel more and more comfortable with coding.