When can we start
I’m always asked, “When can we start piano lessons?” or “How young do you accept guitar students?” The answer to your question lies not within the age of the child but rather their reading level, concentration and maturity level.
I recommend that the better a child can read, the more successful that they will be at reading notes and understanding the musical alphabet. Maybe they can say their alphabet forwards but can they say it backwards? They’ll need to do this a lot if they are playing music. My students that really enjoy reading (usually because they are good at it) love to read the words in their music books and it keeps them interested.
Concentration varies from person to person of course but what I’m talking about is can they sit still? Are they mature enough to follow directions and understand why? I’ve successfully taught three and four year olds because they were used to following instructions and could sit still for 20 minutes.