GINOLJC, to all.
Addressing the OP only, haven't read all of the replies. you had the correct verse to explain this Firstborn question. Colossians 1:18 "And he is the head of the body, the church: who is the beginning, the firstborn from the dead; that in all things he might have the preeminence."
the term head here is the "FIRST", metaphorically speaking, of the authority or direction of God, the Lord Jesus, as husband in relation to his bride, (the Church). Which is backed up by the two words "beginning", and "preeminence."
beginning, it is the Greek word,
G746 ἀρχή arche (ar-chee') n.
1. (properly abstract) a commencement.
2. (concretely) chief (in various applications of order, time, place, or rank).
[from G756]
KJV: beginning, corner, (at the, the) first (estate), magistrate, power, principality, principle, rule
Root(s): G756
this same word is used in John 1:1 concering the Word.
notice definition #2. concretely, the same one person who is the "FIRST" in the Old Creation, (the Ordinal First, the LORD Jesus, title Father) is now concretely,in Flesh, whereas in the OT, he was ABSTRACT, Spirit, now manifested in flesh CONCRETE. and this Manifesting concretely, happen in John 1:1 when he entered into his CREATION as a child. Isaiah 9:6 "For unto us a child is born, (there is your FIRSTBORN), unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counsellor, The mighty God, The everlasting Father, The Prince of Peace."
and this FIRSTBORN has as Colossians 1:18 states, "preeminence".
and preeminence, in the Greek means,
G4409 πρωτεύω proteuo (prō-tev'-ō) v.
to be first (in rank or influence).
[from G4413]
KJV: have the preeminence
Root(s): G4413
There it is again, "to be FIRST" in RANK. just as the word and definition that it was taken from G4413.
G4413 πρῶτος protos (prō'-tos) adj.
foremost (in time, place, order or importance).
[contracted superlative of G4253]
KJV: before, beginning, best, chief(-est), first (of all), former
Root(s): G4253
and the term "foremost" when used as an Adverb, Before anything else. (BINGO). there is GOD Almighty, before David, before Abraham, before Adam, God, the LORD JESUS, now in Flesh concrete, Lord, the FIRST and the LAST,
101G.