I've just stumbled over Irenĉus'
Against Heresies. Irenĉus lived ca. 130-ca. 200 and as a young man he was taught by Polycarp, who in turn had known John the apostle.
Irenĉus wrote a whole chapter named
[. . .] Christ [. . .] was more than fifty years old when He died. It's a bit wordy, so I'll confine myself to quoting the 5. paragraph, where the meat is. Irenĉus argues - as I've just done myself - that in order to be wise, you must necessarily be past your thirties -
and that Jesus was in his forties and fifties when He taught His disciples:
"
They, however, that they may establish their false opinion regarding that which is written, “to proclaim the acceptable year of the Lord,” maintain that He preached for one year only, and then suffered in the twelfth month. [In speaking thus,] they are forgetful to their own disadvantage, destroying His whole work, and robbing Him of that age which is both more necessary and more honourable than any other; that more advanced age, I mean, during which also as a teacher He excelled all others. For how could He have had disciples, if He did not teach? And how could He have taught, unless He had reached the age of a Master? For when He came to be baptized, He had not yet completed His thirtieth year, but was beginning to be about thirty years of age (for thus Luke, who has mentioned His years, has expressed it: “Now Jesus was, as it were, beginning to be thirty years old,” when He came to receive baptism); and, [according to these men,] He preached only one year reckoning from His baptism. On completing His thirtieth year He suffered, being in fact still a young man, and who had by no means attained to advanced age. Now, that the first stage of early life embraces thirty years, and that this extends onwards to the fortieth year, every one will admit; but from the fortieth and fiftieth year a man begins to decline towards old age, which our Lord possessed while He still fulfilled the office of a Teacher,
"
So Irenĉus agrees with me, but there's much more to it. According to Irenĉus, several of the apostles have confirmed that Jesus was in his fifties when he taught:
" (5. cont.) [. . .]
even as the Gospel and all the elders testify; those who were conversant in Asia with John, the disciple of the Lord, [affirming] that John conveyed to them that information. And he remained among them up to the times of Trajan. Some of them, moreover, saw not only John, but the other apostles also, and heard the very same account from them, and bear testimony as to the [validity of] the statement. [. . .]
"
So Irenĉus backs his opinion on the testimony of
several elders - not just Polycarp - who have spoken with
several apostles - not just John.
There we have it brethren and sistern - right from the horse's mouth: The rumor of Jesus being an adolescent zit-face is as false as Ratzinger's teeth. No mere tradition could be more creditably authorized than this.