I play flute and was inspired by a friend of my dads who used to come play at my house (my dad played piano and regularly had other musicians over).

I begged to play and wasn't allowed to start until my arms could reach, so about 8. I practiced every day and quickly progressed. I did exams and eisteddfods but also did music for HSC. I still play but I also really really wish I had learnt piano because my knowledge of chords and musicianship has been hampered by playing only a melodic instrument

In contrast my older sister played piano from five and was forced to practice and hated it. She still gets nervous playing piano despite loads of talent and thousands of dollars of tuition and thousands of hours playing.

In short I think the motivation needs to come from the child. I used to play to the trees in the garden and help them grow. I loved playing my flute and practice was a joy. I don't believe my sister learnt anything from being forced to practice except resentment for the instrument.

Child-led is the best way to go. Encourage, inspire and facilitate learning, but don't force.