Music instrument classes - how young etc?

[Anonymous]

Private piano lessons starting in K. One child took for 9 yrs, one child for 2. Serious intense teacher. Fast forward (in case this is of any interest ..) Child who took for 9 yrs also did HS band and could switch instruments easily and play at the highest level in HS. Child who stopped piano after 2 yrs, didn't do any music until college then taught himself guitar and now is a paid performer (when he chooses to be)

It's a journey. Don't fret the "how". If it's a skill/passion, it'll happen sometime.