Your priest is misinformed. The Church's Catechism can and should be read by all Catholics (some might say especially by associate pastors). The language is not at all technical and is within the grasp of the average adult Catholic.
The Catechism is laid out in an orderly, systematic style with copious citations to Scripture, to the Fathers of the Church, and to the ecumenical councils. Of particular help are the summary statements at the end of each section. The Church desires that all Catholics - especially lay Catholics - study the new catechism as a means of growing in knowledge of the faith.
Many Catholics are confused about what the Church really teaches because they have received conflicting messages from priests, nuns, and others. Perhaps one reason some are opposed to the promulgation of this Catechism is that they'll no longer be able to say the Church has "changed its teachings" on issues such as purgatory or Marian doctrines, or that there is no official teaching on issues such as contraception and homosexuality. Buy two copies: one for yourself and one as a gift for your associate pastor.