I was looking over an article by an anti-Catholic apologist, examining examples of “allegedly early veneration of Mary” and the thought came to me: “the earliest veneration of Mary is in the Bible itself!” I submit that we see it in [mother of John the Baptist] Elizabeth’s response to Mary:
Luke 1:39-44 (RSV) In those days Mary arose and went with haste into the hill country, to a city of Judah,  and she entered the house of Zechari’ah and greeted Elizabeth.  And when Elizabeth heard the greeting of Mary, the babe leaped in her womb; and Elizabeth was filled with the Holy Spirit  and she exclaimed with a loud cry, “Blessed are you among women, and blessed is the fruit of your womb!  And why is this granted me, that the mother of my Lord should come to me?  For behold, when the voice of your greeting came to my ears, the babe in my womb leaped for joy.
Of particular noteworthiness is Elizabeth’s jubilant and Spirit-filled exclamation (Lk 1:42), “Blessed are you among women . . .!” The following 25 English translations bring out the extraordinary nature of this, more so than the most common rendering, seen above:
Amplified Bible Blessed [worthy to be praised] are you among women . . .
Amplified Bible, Classic Edition Blessed (favored of God) above all other women are you!
Common English Bible (CEB) God has blessed you above all women
Contemporary English Version (CEV) God has blessed you more than any other woman!
Easy-to-Read Version (ERV) God has blessed you more than any other woman
Expanded Bible (EXB) God has blessed you . . . more than any other woman
God’s Word Translation (GW) You are the most blessed of all women
Good News Translation (GNT) You are the most blessed of all women
Living Bible (LB) You are favored by God above all other women
Name of God Bible (NOG) You are the most blessed of all women
New Century Version (NCV) God has blessed you more than any other woman
New International Reader’s Version (NIRV) God has blessed you more than other women
New Life Version (NLV) You are honored among women!
New Living Translation (NLT) God has blessed you above all women
New Testament for Everyone (NTE) Of all women, you’re the blessed one!
The Passion Translation (TPT) Mary! You are a woman given the highest favor and privilege above all others
Worldwide English New Testament (WE) God has made you happy and blessed you more than all other women
Holman Christian Standard Bible You are the most blessed of women
Smith’s Literal Translation Praised thou among women
New English Bible (NEB) God’s blessing is on you above all women
Revised English Bible (REB) God’s blessing is on you above all women
Barclay You are the most blessed of women
Jerusalem Bible Of all women you are the most blessed
Kleist & Lilly Blessed are you beyond all women!
Goodspeed You are the most favored of women
I would say, “how is this not veneration, by any sensible definition of the word, as used by Catholics, Orthodox, and some Protestants who agree with them?” Everything is right there: “praise” (Amplified, Smith’s Literal), “honor” (NLV), “blessed” above or more than “any other” or “all” women (many), “favor[ed]” (Amplified Classic, Living, Goodspeed, TPT), and “highest privilege” (TPT). What else is needed? This is most definitely veneration, which is essentially synonymous with “high honor and respect.”
Moreover, Catholics are quick to point out that all veneration is grounded in God’s enabling grace towards the person or angel venerated. All honor goes to Him. All good things and holiness and righteousness and love come from Him. Therefore, when we venerate a holy person or angel, we are ultimately giving praise and glory to God (just as the reflected light of the moon actually comes from the sun): without Whom the person or angel would not be holy in the first place, and able to be venerated.
Absolutely every good action is caused by God’s prior enabling grace. That is Catholic dogmatic teaching. And sure enough, how Mary responds to Elizabeth precisely illustrates or exemplifies this Catholic teaching:
Luke 1:46-50 And Mary said, “My soul magnifies the Lord,  and my spirit rejoices in God my Savior,  for he has regarded the low estate of his handmaiden. For behold, henceforth all generations will call me blessed;  for he who is mighty has done great things for me, and holy is his name.  And his mercy is on those who fear him from generation to generation.
Note all the elements involved in Mary’s exclamation: 1) she immediately gives glory to God (1:46), rejoices in Him (1:47), calls Him her “Savior” (1:47), notes her own “low estate” [humility] (1:48), notes that her being called “blessed” is because of God (1:48-1:50), says it is God Who has “done great things” for her (1:49), acknowledges His holiness (1:49), and His mercy (1:50).
Mary takes no credit for herself; all goes to God. And this is why we venerate holy people, because they always do this. Venerating them is not antithetical or contrary to worshiping and adoring God; it’s part of that, while we make a sharp distinction between the veneration or honor of saints and angels, over against worship and adoration: reserved for God alone. The Blessed Virgin Mary expresses the same notion that St. Paul emphasizes:
1 Corinthians 15:10 But by the grace of God I am what I am, and his grace toward me was not in vain. On the contrary, I worked harder than any of them, though it was not I, but the grace of God which is with me.
2 Corinthians 6:1 Working together with him, then, we entreat you not to accept the grace of God in vain.
Galatians 2:8 (for he who worked through Peter for the mission to the circumcised worked through me also for the Gentiles),
Galatians 2:20 I have been crucified with Christ; it is no longer I who live, but Christ who lives in me; . . .
Philippians 2:13 for God is at work in you, both to will and to work for his good pleasure.
This is the Bible, and this is Catholicism. The glory always ultimately goes to God. But He allows us to work “together with Him” and He works through us to accomplish His ends. We in turn venerate and honor exceptional people who exemplify this cooperation with God’s grace in an extraordinary way (Mary above all). It’s totally and explicitly biblical, and there is nothing whatsoever unbiblical in any of this. If we’re looking for “early veneration of Mary” we need go no further than the Gospel of Luke, chapter 1. And the veneration there is directly as a result of being “filled with the Holy Spirit.” Thus it is inspired Scripture (God’s revelation) and Spirit-inspired action.