To some extent, I guess that's what I've tried to do here. The linear algebra might be too advanced for a 12 year old (I didn't pick it up until much later!), but on the other hand you don't need to follow all the derivations - a 12 year old can learn a lot just by following the results and the resulting algorithms.

There's also a linear algebra appendix [0] that presents the operations, explains how to use them, and how they can be interpreted, without going in any theoretical depth about why these things are the way they are.

[0] https://gabrielgambetta.com/computer-graphics-from-scratch/A...