By Catechism, I am going to assume knowledge of the doctrines and practices of the Catholic Church, right?
Part of this is because for years the Church has put the cart before the horse (or the Catechism before the horse).
Think of a sport like baseball. If you grab your child and take them to a baseball game for the first time, they may get caught up in the emotional excitement from the people around them, but, they are not likely to begin pouring over stats and history and making fantasy baseball teams. In fact, they may find baseball to be boring and decide as soon as they are old enough they will never go to another baseball game.
If, however, that child sees their parent as a baseball player, where it is part of family life instead of a spectator sport, they are more likely to want to learn the history, the stats, the intricacies of the game.
In our world today, and for the past generation or two, school is about passing the test. After the test, they don’t need that knowledge and they cram for the next test. Sacramental prep has become the same thing.
We need to foster a love of the Faith by becoming and modeling discipleship, others become disciples. When you are a disciple, you hunger to learn!