D.M.
I'm not sure what age piano is good to start, but dance and gymnastics, age 3 would be good. Ice skating would be 3 or 4. My daughter took all those things, and ice skating is a little frustrating if they are so young. They even have dance and gymnastics for two year olds. One warning though - only plan one or two activities at any given time - too many activities and they will get burned out, especially once they start school. Kids need down time. To find good activities in your area, look in the San Diego Family magazine, and look online. There's a place called My Gym for little ones, and also JW Tumbles, and for dance, google San Diego Civic Dance Arts, and there are places all over San Diego where they can start a group dance class for a reasonable price.