That's how I got my start. After TI-BASIC, Z80 assembly was the second programming language I learned, at age 12. It turned out to be a great foundation. For one thing, it was fairly easy to understand, from a syntactic perspective. Secondly, it gave me a much better foundation for understanding the lower-level aspects of C, letting me concentrate more on understanding the more complicated abstractions, and what they actually represent.
I have been reading that very same book, but third edition, which focuses on GNU/Linux as platform, and it's way better.
Also, you can "find online" the pdf for the third edition.