I wanted to follow up with a recommendation for others who may be in the same boat. I picked up a copy of "Music Theory in One Lesson" by Ross Trottier. It's a short book (52 pages), and Trottier is an engaging presenter (his YouTube channel "Ross the Music Teacher," has good material).
Unfortunately, somewhere between the Chromatic scale, and the Major Scale, I got lost. Not his writing, Just a function of my ignorance.
After that minor frustration, I went in search of a more remedial text.
What I found (and actually needed) was not a remedial, but a comprehensive introduction, that was structured in a way that I could follow (We used to call this 'breaking it down "Romper Room style"'). I was rewarded with "Basic Music Theory, 4th edition" by Jonathan Harnum (he starts with the staff, the clefs, and rhythm, rather than scales).
It's informative, well written, and fun. Well... It's fun for ME, because I want to learn the things contained therein, and Harnum writes well (but my 13-year old son may not be as captivated).
Best to you.