Pony,if you make your kids into virtuosos by whatever age,you'll be no better than your dad;your dad taught English,wanted you to read shakespeare.you play guitar,want to kids to follow suit.You might even be worse,coz you already know how it feels to be made to do something you don't want,or to be made not to do something you want(for those who aren't terribly bright,that is not some bright play with words,it's the two sides of the coin;)).Maybe your dad didn't know how you felt(something you might want to ponder),but you do.Don't do it.
About why I play:for anything and everything I might get out of it;therapy,enjoyment,money,fame,whatever.
Music has a lot to offer.Take what you need from it.