I taught guitar lessons for a living for ten years. In that time, I witnessed many children struggle with the instrument. Some of them persisted and triumphed, while others gave up. However, I began to believe that most of the struggle was unnecessary and unproductive, even for those who succeeded. I therefore began seeking a better way to teach.
I now strongly recommend that younger children start learning on a ukulele rather than a guitar. A ukelele is much simpler and easier to hold and play, it allows hand strength to develop slowly, and is overall a relatively painless and frustration-free entry-level instrument. Ukuleles are also available at a fraction of the price of guitars, and the knowledge is easily transferable to guitar, should the student wish to switch after a year or more of lessons. I also have developed a special curriculum for young kids that helps make learning easy and fun.
For more information about my ukulele curriculum, please visit http://www.misscharlottemusic.com/lessons.html
You can see some of the songs other kids are learning on my YouTube Channel: https://www.youtube.com/channel/UCWstTmX6guYOfaUzmZJpy3g