Initially, I decided not to post anything on this thread. However, having raised two fine children of my own, I can unequivocally tell you that the best thing to do is allow them to be kids for a while. They'll discover lots of neat things while growing up, and while they're walking along this path you should be with them every step along the way.
Eventually, they'll decide on their own if they wish to pursue music, either as a hobby or as a career. There are loads of great teaching aids for budding piano players, some of which are online, and one that I highly recommend for youngsters of all ages is Scott Houston's, which can be found
here. For many years I wrote a column that entitled "Take A Kid Fishing," which is something I did with both of my children. They learned a lot just by having fun with good old Dad and catching loads of monster bluegills, bass and catfish. I taught them the basics, how to tie knots correctly, how to bait a hook, how to cast safely, how to hook and land a fish, and how to release the fish with the least amount of injury. After all these years, they still love to go fishing with Dad.
When it came to music, my son picked up a guitar, and taught himself how to play. He quickly learned more chords than I knew existed, his chops were incredible, and within a year he was playing in a rock band. A year later, the band went on a nationwide tour and booked an European tour. Unfortunately, a couple of the band members got involved in drugs about halfway through the U.S. tour. My son packed his gear, climbed aboard a bus and came home. He still gets together with some old friends and jams once in a while, but that's as far as it goes.
My daughter loves music. But, she has absolutely no interest in playing. She's a great singer, but again, no interest in learning how to perfect her voice and sing professionally.
If I had to raise two more children, even at this stage in life, I wouldn't change much of anything I did. I would still opt to let them be kids, take them fishing and boating, and encourage them in any endeavor they choose.
Good Luck,
Gary