Young vs mature Coconuts

Just back from a week in Bali - Kuta, doing nothing because I'm terminally ill. So enjoyable, staff at hotel excellent (5 yo daughter said "the people here are working so hard to make me happy". She was right)

 Anyway, to the point... my partner is Vietnamese and has always drunk mature (not old) coconut juice, never "young" coconuts. But in Bali, it was always young ones. She didn't complain, just didn't enjoy the taste as much.

 So, is there a Balinese member here who could explain the Balinese preference for young, as opposed to older, coconuts. We're both just genuinely curious.