There is a Long Answer and a short one.
The short answer ….it all depends on the kid, approach and the expectations.
Here it comes– brace yourself, pour a drink: The Long Answer.
Kids learn through a feedback loop, and progress is determined by their developmental readiness in response to their environment and their temperment. When children are given stimulus to emulate, especially stimulus which relates to them and to which they can relate– they take off in the areas that engage them. I am sure you have either experienced or heard from parents how much faster younger siblings walk, talk etc… than their older counterparts. One reason is that they are surrounded by stimulus relating to them, showing them how to be a child.
Music, like language, is learned initially through a feedback loop. It is a rare youngster who, at 5, is ready to physically finger chords or is mentally able to sit and play for more than a few moments. But that does not mean that they are not learning! They are learning all the time, and music is no exception.
The illustrations in the book, the fun pictures and the chord diagrams, give a visual focal point for the youngest kids. Many wee folk love to look at pictures. The recordings create the feedback loop of sound. Kids learn intervals, melodies, and lyrics with alacrity. When we know a song a song by heart before we try to learn to play it on an instrument, the outcome can be pure joy (and less frustration).
Having an instrument on hand which children can play with, and eventually play, is a great thing at any age. $35 models are well suited for this. Instruments, not toys; nothing precious–if they get broken… meh.
Tune them as often as you can. Write “G” “C” “E” “A” on the tuning pegs and number the strings with a sharpie! Put a sticker on the fretboard where a finger should be placed to make a C chord. Let a kid put stickers on the body with impunity! Draw a smiley face on the top/side of the instrument to re-enforce “this end up”.
On the whole, I see kids in 3rd and 4th grade having the motor skills and the ability developmental maturity to really learn. That is when I can take a classroom of 30+ kids and, in the course of a few weeks, get them to play songs with 4 chords.
Ready or not…. here she comes! AKA musician’s kid having fun in a dressing room.
I have known a few kids- very few- who are really ready to play at 5 or 6. Often they are kids of musicians who have grown up in households filled with experimentation, rehearsing; who have watched their parents sweat and rejoice the same way they do. Kids who are driven to practice, and know how to do it. It is pretty rare. (In fact, just as many musician’s kids are apathetic towards the idea of playing or performing)
I do know that young kids who learn along side their parents learn better. Children learn through watching us model behavior far more readily that they do through instruction. Some parents who feel insecure about their abilities worry about modeling effectively. I don’t. I think kids “ears” grow irrespective of an adult’s shortcomings in pitch or rhythm. To see a parent try, struggle, unafraid of failure… that is big. Perhaps even bigger than learning ukulele.
In private lessons or small groups I see kids at 6-8 able to focus and enjoy their achievements. I do private lessons for families in their homes. A parent or two, and a couple of siblings, together sitting on the floor. Rarely will a child of 5 or younger participate for more than 5 minutes. Older kids may hang in for 15 or more, then the parent fills the allotted time …and then some. The following week I will often hear that the little kid, whom the parents thought was not engaged, was singing the song we covered and messing around with their instruments the next day.
So- for the experience of making music, the recorded music- your kid is ready, regardless of age.
To play- for the first 3 songs (in our book) they can be quite young, 4 and up.
To really play– probably 7-9.
They are NEVER too young to see and hear YOU learn to play!
What are you waiting for?!