Pope Paul VI set forth requirements for the permanent diaconate:
4. By the law of the Church, confirmed by the Ecumenical Council itself, young men called to the diaconate are obliged to observe the law of celibacy.
5. The permanent diaconate may not be conferred before the completion of the 25th year. Nevertheless, an older age can be required by the episcopal conferences.
I don’t believe this requirement is in force for seminarians who “pass through” the diaconate on their way to presbyteral ordination.
6. Let young men to be trained for the diaconal office be received in a special institute where they will be put to the test and will be educated to live a truly evangelical life and prepared to fulfill usefully their own specific functions.
Note the purpose of the “special institute.” Diaconal candidates are to be tested. Then education for an “evangelical life.” How do you suppose an “evenagelical life” is defined? The preparation for diaconal functions is rather broad. It might mean education or formation. Apprenticeship is a style that could more often be utilized.
Any deacons or others with comments on the age requirement? Have any dioceses chosen a different mininum age?