I happened to meet a mother accompanying her six-year-old to music class this morning.
The mother's parting words to me were: "Whole note, half note, quarter note!"
I winced. Starting with arithmetic dumbs down every aspect that distinguishes music from everything else. It merely reinforces the child's ability to count and, by connecting it to a printed symbol, locks up rhythm once and for all in a tidy concrete container.
Why not start with a finger cymbal or a traingle? A bell?
Give a kid magic any day, every day.