I hate to say it, but I have the feeling that our culture is breeding a sense of music as something clean, sterile, vacuum-sealed, quantifiable--anything but personal.
If personal, how? I keep coming back to the same point: As soon as you catch yourself saying "I like it" or "I don't like it", even if you say whichever to yourself in silence, at that moment it has become personal.
But the rub lies in the words: "As soon as..." My guess is that in the race to produce quantities of notes children are discouraged from noticing the qualities of particular sounds.
The answer has to be "As soon as you make the first sound."
Alexandra Horowitz, in Inside of a Dog, describes the two-way transaction involved in getting to know a new dog. Each creature reaches out to the other in a delicate exchange of sensations and expectations. I think of her description when describing how we reach out to sounds, taking them in, as it were, before they actually reach us.
In this way music is part of us before it even sounds.