compare Luke 3:1And in the fifteenth year, in the reign of Tiberius Caesar, the word of the Lord came to John, the son of Zacharias
ἔτει δὲ πεντεκαιδεκάτῳ ἐπὶ Τιβερίου Καίσαρος ἐγένετο ῥῆμα κυρίου ἐπὶ Ἰωάννην τὸν Ζαχαρίου υἱόν
Then Clement immediately goes on to say:Ἐν ἔτει δὲ πεντεκαιδεκάτῳ τῆς ἡγεμονίας Τιβερίου Καίσαρος, ἡγεμονεύοντος Ποντίου Πιλάτου τῆς Ἰουδαίας, καὶ τετρααρχοῦντος τῆς Γαλιλαίας Ἡρῴδου, Φιλίππου δὲ τοῦ ἀδελφοῦ αὐτοῦ τετρααρχοῦντος τῆς Ἰτουραίας καὶ Τραχωνίτιδος χώρας, καὶ Λυσανίου τῆς Ἀβιληνῆς τετρααρχοῦντος, 2 ἐπὶ ἀρχιερέως Ἅννα* καὶ Καϊάφα, ἐγένετο ῥῆμα Θεοῦ ἐπὶ Ἰωάννην* τὸν Ζαχαρίου υἱὸν ἐν τῇ ἐρήμῳ.
compare that to Luke 3:23:And again in the same book
καὶ πάλιν ἐν τῷ αὐτῷ·
"And Jesus was coming to his baptism, year 30,"
ἦν δὲ Ἰησοῦς ἐρχόμενος ἐπὶ τὸ βάπτισμα ὡς ἐτῶν λʹ
And continuing where we left off in Clement:Καὶ αὐτὸς ἦν Ἰησοῦς ἀρχόμενος ὡσεὶ ἐτῶν τριάκοντα,
compare this to the lengthy section at the end of chapter 4:And that it was necessary for Him to preach only a year, this also is written:
καὶ ὅτι ἐνιαυτὸν μόνον ἔδει αὐτὸν κηρῦξαι, καὶ τοῦτο γέγραπται οὕτως·
"He hath sent Me to proclaim the acceptable year of the Lord."
ἐνιαυτὸν δεκτὸν κυρίου κηρῦξαι ἀπέστειλέν με.
In my estimation the only way any of this makes any sense is if the three sections cited by Clement appeared one after another almost or exactly in succession i.e:Καὶ ὑπέστρεψεν ὁ Ἰησοῦς ἐν τῇ δυνάμει τοῦ Πνεύματος εἰς τὴν Γαλιλαίαν· καὶ φήμη ἐξῆλθεν καθ’ ὅλης τῆς περιχώρου περὶ αὐτοῦ. 15 καὶ αὐτὸς ἐδίδασκεν ἐν ταῖς συναγωγαῖς αὐτῶν, δοξαζόμενος ὑπὸ πάντων. Καὶ ἦλθεν εἰς Ναζαρά, οὗ ἦν τεθραμμένος, καὶ εἰσῆλθεν κατὰ τὸ εἰωθὸς αὐτῷ ἐν τῇ ἡμέρᾳ τῶν σαββάτων εἰς τὴν συναγωγήν, καὶ ἀνέστη ἀναγνῶναι. 17 καὶ ἐπεδόθη αὐτῷ βιβλίον τοῦ προφήτου Ἠσαΐου*, καὶ ἀναπτύξας* τὸ βιβλίον εὗρεν τὸν τόπον οὗ ἦν γεγραμμένον Πνεῦμα Κυρίου ἐπ’ ἐμέ, οὗ εἵνεκεν ἔχρισέν με εὐαγγελίσασθαι πτωχοῖς, ἀπέσταλκέν με ⧼ἰάσασθαι τοὺς συντετριμμένους τὴν καρδίαν⧽, κηρῦξαι αἰχμαλώτοις ἄφεσιν καὶ τυφλοῖς ἀνάβλεψιν, ἀποστεῖλαι τεθραυσμένους ἐν ἀφέσει, κηρῦξαι ἐνιαυτὸν Κυρίου δεκτόν. 20 καὶ πτύξας τὸ βιβλίον ἀποδοὺς τῷ ὑπηρέτῃ ἐκάθισεν· καὶ πάντων οἱ ὀφθαλμοὶ ἐν τῇ συναγωγῇ ἦσαν ἀτενίζοντες αὐτῷ.
Of course in order to justify this reconstruction you have to drop the ἐτῶν λʹ = 'year 30' but does it make any sense there without a verb or anything connecting it to baptism reference before it? In our Luke there is no connection between the 'thirty years old' reference and baptism. It is as if an editor has come along and added the reference to the text.And in the fifteenth year, in the reign of Tiberius Caesar, the word of the Lord came to John, the son of Zacharias, there was Jesus coming to his baptism [saying] "He hath sent Me to proclaim the acceptable year of the Lord."
My assumption would be that the original gospel said Jesus came to John's baptism directly from heaven (he was in the water with John?).