Molly and Mommy play a duet

Since I started playing the piano regularly a few weeks ago, Molly has become very interested and wants to help!

You can see her face better in this one, but please excuse my playing!

Any thoughts or suggestions regarding when to start piano lessons? I don't think it would work well for me to teach her, and I'm not sure at what age most teachers begin accepting students. I was 4 or 5 when I first started, but didn't really get into it until I was 10...