That's a very nice draft! It starts basic and soft but then it jumps to _high-level_ notions. I don't know if average children will understand. For instance, in the _What is a Programming Language_ section, you could explain what a compiler is compared with other way to run code, and what is the compilation process. Or before starting with syntax in _Part II: The basics_ , perhaps introduce what is the general structure of a Nim program, single or multiple sources. Last example, is explaining pointers in _References and Pointers_ a notion that must be introduced to child-programmers? I would wait until _Part V: Advanced topics_ section to write about pointers...
A way to reach for children and beginners is to become quickly practical with examples or projects that they can try and extend on their computers. An example from Canada: [https://kidscodejeunesse.org/resources-for-educators](https://kidscodejeunesse.org/resources-for-educators). There must be other resources in other countries. Is there a way to report more precise critics directly in the text and help you?