In the Book of Proverbs it is written, "Educate the Child according to his way; even when he is old he will not depart from it" (Proverbs 22:6).
However, one should not educate the child to believe something that is correct only for one's childhood and has to be changed for more correct beliefs later on—"He'll understand when he grows up."
On the contrary, the child has to be helped to understand in accordance with his capacities, and what he learns has to be correct, so that even when he grows up he won't find any discrepancies —it will still be correct.
–Rabbi Adin Steinsaltz
From The Sustaining Utterance by Rabbi Adin Steinsaltz