I will offer my experience and not my advice.

My DD6 (almost 7) takes piano lessons, and she has since she was 5. DS3 will take piano lessons, maybe starting next year. Piano lessons are not optional in our house. We consider it a part of a well-rounded education. If the kids want to switch to another instrument (or voice)in middle school, when school lessons are offered, then they may. DH and I also take piano lessons, BTW.

DH grew up in a musical family and took piano for just a couple of years and then switched to trumpet and baritone horn. He was/is a gifted musician, but his career is not in music. I took piano for a few years, but did not mesh well with my teacher and quit. I moved on to voice lessons in MS and HS. Music is not my talent, but I enjoy it and value the experience. I also love the piano and enjoy taking lessons as an adult, even if I suck at it.

DD clearly has DHs talent. She goes through spurts of liking to practice and spurts of complaining. But she does LOVE to perform. Oh, does that ever motivate her! The periods in between recitals and competition she will express not wanting to practice or go to lessons. She knows it isn't an option- it is like school. You just do it because it is important to learn.

We feel like she can make the choice as she approaches middle school age. Until then, we make the choice for her. Her other after-school activities are HER choice. But not piano. That's what works for our family. I do think it helps that we all practice and play- hearing mommy make mistakes and curse her fingers and try again is always reassuring;-)