You can start as an adult, because you know exactly what you want and will consciously go after it. Your hands will not be as flexible, though. Teenagers are typically not very patient, and if by their teens they hadn’t developed proper discipline and work ethics at dealing with a musical instrument yet, it would be rather difficult to make them do correct things on the piano. It usually takes years to obtain the necessary momentum to overcome the toughest part of any study – the beginning.  It’s better to begin earlier.

I would say, it would be really good to start at the age of 5 or 6, but for a child that young it would be necessary to break a lesson into a few short sessions and change the subject and approach very often. Young children are very intelligent, and they learn anything new with joy and amusement.

At the same time, having in mind that typically you would bring your five-year-olds to a teacher just once a week, you will absolutely have to ask them to repeat everything that they had learned at the lesson 3-4 times EVERY DAY (very shortly each time). If you don’t do that, most likely it will not work. Children’s memory is short, while the amount of information they absorb every day is huge. They can memorize something fairly quickly, but then as quickly forget it, too – if YOU skip YOUR days with them. For to help young children memorize something well, we absolutely have to repeat things with them many times. Many of them gladly do it themselves during the day – suddenly run to the piano, play the songs that they are studying, and then return to what they were doing before, just as if nothing had happened. They often like to perform for other people, by the way. 🙂

You can easily prepare your young kids for music classes a lot earlier, though. Just turn on your player with some nice classical stuff, turn it down, so that it would be just a background track, and let it play for a couple hours every day. This way it will not bother anybody, and it will open the door for your children to further understanding and appreciation of classical music. Believe me, those, who appreciate classical music, can have a good understanding of any kind of music at all; they can easily relate to jazz, or rock, or folk, or even progressive metal. A great number of prominent jazz pianists had classical background. Among others, we can recall the names of Oscar Peterson, Nat King Cole, Bud Powell, Bill Evans, Dave Brubeck, Michel Petrucciani, Chick Corea, Herbie Hancock… Jordan Rudess, a brilliant musician, who plays in the progressive metal/rock style, dropped off Julliard School of Music, where he studied classical piano, by his late teens. Now he urges younger folks to practice arpeggios and all kinds of exercises for developing proper technique.   

Think about it one more time. It’s not about the age of your children, who you want to study the piano; it’s about your devotion and willingness to help them. Every day, for a number of years. Are YOU ready? 🙂