The best time to teach children to develop a musical skill is when they are young, from 2-7 years old. During those years, their brains are like dry sponges that hold as much liquid as they can. When the sponge gets old, it still holds liquid but not as much as when it was new. It does not have to be a grand piano. A small digital keyboard without legs will do just fine so the child can get started. Look at how the casio privia px-150 is designed. Without the stand, simply put it on a table. Attach it when needed to make learning more comfortable.