Taking piano lessons is a bit controversial with me. The majority of people who ever learned via lessons cannot play a lick today. Why? Because all they learned was how to sight read. Which they forgot, over time. If a child takes lessons and never learns how to play by ear, in 20 years, she probably will have forgotten how to play. And certainly will be lost without sheet music in front of her. I don't know all the answers but whatever it takes, I'd encourage learning to play by ear in addition to sight reading.