The General Directory For Catechesis speaks of 7 foundation stones or basic elements of all catechesis.  They are essential for catechesis to be complete.  Whether you are speaking to 1st graders or to 12th graders these elements should be included.   Paragraph #130 of the GDC says the following:

The Catechism of the Catholic Church, for its part, brings to catechesis “the great tradition of catechisms”. (443) In the richness of this tradition the following aspects deserve attention:

– The cognitive or truth dimension of the faith: this is not only living attachment to God but also assent of intellect and will; the catechisms constantly remind the Church of the need for the faithful to have an organic knowledge of the faith, however simple in form;

– An education in the faith, which is well rooted in all its sources, embraces all the different dimensions of faith profession, celebration, life and prayer.

The wealth of the patristic tradition and the tradition of catechisms comes together in the actual catechesis of the Church, enriching her in her own concept of catechesis and of its contents. These traditions bring to catechesis the seven basic elements which characterize it: the three phases in the narration of the history of salvation (the Old Testament, the life of Jesus Christ and the history of the Church) and the four pillars of its exposition (the Creed, the Sacraments, the Decalogue and the Our Father). With these seven foundation stones, both of initiatory catechesis and of continuing Christian development, various schemes and styles may be devised, in accordance with the different cultural situations of those to whom catechesis is addressed.