Sometimes starting kids a little later on music lessons may be better. We tried my son at age 5 on the piano and it was just too much for him. We reintroduced it at age (almost) 8- he's been taking weekly lessons now for over a year and he loves it.
He practices every day without problems- he won a couple of medals and trophies recently at some local competitions.
We are in California and see ALOT of "Tiger moms" start their kids at age 3 on piano or violin. However, when my son came up against their kids at the competitions, many of them were at the same level as him although they had been playing longer. The kid needs to be ready too.