Solon, fr. 27 (=Philo, de opif. mundi 104)
“A child, when still young and small, grows
a bulwark of teeth and loses them in his first seven years
When the god brings about the second seven years
He starts to show the signs of adolescence
In the third set of seven, his chin starts to fuzz
As his limbs thicken and skin changes color.
In the fourth seven, every one is seriously the best
In terms of strength, and men begin to show the signs of excellence.
In the fifth season, it is the time for a man to think about marriage
And to seek the generation of children afterwards.
In the six season, a man’s mind is fit for everything,
And he no longer wishes to act out in reckless deeds.
In the seventh season, and the eighth each is best
In thinking and speaking–fourteen years for both!
In the ninth season, a man can do anything, but
His speech and mind are less sharp, beneath peak excellence.
If someone completes the tenth stage and comes to the end,
his appointment with death is not out of season.”
παῖς μὲν ἄνηβος ἐὼν ἔτι νήπιος ἕρκος ὀδόντων
φύσας ἐκβάλλει πρῶτον ἐν ἕπτ᾿ ἔτεσιν.
τοὺς δ᾿ ἑτέρους ὅτε δὴ τελέσῃ θεὸς ἕπτ᾿ ἐνιαυτούς,
ἥβης ἐκφαίνει σήματα γεινομένης.
τῇ τριτάτῃ δὲ γένειον ἀεξομένων ἔτι γυίων
λαχνοῦται, χροιῆς ἄνθος ἀμειβομένης.
τῇ δὲ τετάρτῃ πᾶς τις ἐν ἑβδομάδι μέγ᾿ ἄριστος
ἰσχύν, ᾗ τ᾿ ἄνδρες σήματ᾿ ἔχουσ᾿ ἀρετῆς.
πέμπτῃ δ᾿ ὥριον ἄνδρα γάμου μεμνημένον εἶναι
καὶ παίδων ζητεῖν εἰσοπίσω γενεήν.
τῇ δ᾿ ἕκτῃ περὶ πάντα καταρτύεται νόος ἀνδρός,
οὐδ᾿ ἔρδειν ἔθ᾿ ὁμῶς ἔργ᾿ ἀπάλαμνα θέλει.
ἑπτὰ δὲ νοῦν καὶ γλῶσσαν ἐν ἑβδομάσιν μέγ᾿ἄριστος
ὀκτώ τ᾿· ἀμφοτέρων τέσσαρα καὶ δέκ᾿ ἔτη.
τῇ δ᾿ ἐνάτῃ ἔτι μὲν δύναται, μαλακώτερα δ᾿ αὐτοῦ
πρὸς μεγάλην ἀρετὴν γλῶσσά τε καὶ σοφίη.
τὴν δεκάτην δ᾿ εἴ τις τελέσας κατὰ μέτρον ἵκοιτο,
οὐκ ἂν ἄωρος ἐὼν μοῖραν ἔχοι θανάτου.
I checked with my wife–a pediatric dentist–and first dentition is complete between ages 3-6. Also, we got married when I was 29 and had kids in our 30s (oops, another in our 40s). And then, in my seventh season I am definitely the best so far at speaking and thinking (and I can’t bench what I could at 25), so Solon is onto something.
This is hard to convey to someone who hasn’t read a lot of Greek poetry, but Solon is not much of a poet.