My daughter (age 5) took piano lessons and Music Mind Games from Michiko Yurko (the creator of MMG). This, along with my work teaching Suzuki piano, is what led me to go to a week long training in Music Mind games. Which in turn allowed me to understand how a similar method and materials could be used to teach Byzantine chant theory.
To get to the point, I developed the Parallage Phrases with my daughter in mind and have tested them on her every once in a while. So, in that way, she is my first student even though we haven't had very formal lessons yet.
Amazingly enough, she made it to phrase 20 without too much difficultly! Afterwards, she asked me for a piece of paper and a pencil. She started composing in Byzantine notation, all on her own, without any prompting from me! I taped the tail end of it, because I thought it was so interesting to hear her vocalize what she was writing. I love hearing her say "down 2" like it's no big deal; even though she just learned the symbol 15 minutes ago!
Here is her finished composition. It's amazing what children are capable of doing!