dang it, i just got a 2 yr old chief and wanting some more rare collectabless.............oh well, patience is a virtue
Your chief should be able to point out collectables just fine, just like my 7-year old chief can make food and direct work; children simply cannot teach other children, just like you can't use a 14-year old girl as a brood mare. It makes sense in real life, so this is how it's portrayed in the game.
I admit that it is a little confusing that the age requirements for these tasks are not consistent with the other tasks available to your villagers, but what are you going to do?