So, since we are not to engage in private interpretation, where is this taught officially? And what century did “she” in "she shall cursh thy head" find its way into that verse?
Let the Catholic Encyclopedia answer that,
The translation “she” of the Vulgate is interpretative; it originated after the fourth century, and cannot be defended critically. The conqueror from the seed of the woman, who should crush the serpent’s head, is Christ; the woman at enmity with the serpent is Mary. http://www.newadvent.org/cathen/07674d.htm
He gave Mary the title "Full of Grace". Chaire, Kecharitomene Full of Grace. No sin at all.
You are again mistaken. Mary is called "full of grace" by Catholics, yet the Scriptures do not say she was "full of grace," as "charitoo" in Lk. 1:28, is never used for "full" elsewhere, but Lk. 1:28 simply says “Hail [chairō=rejoice, greeting, etc.] grace [chairō, denoting to be graced, favored, enriched with grace as in Eph.1:6. .
Much more technical here:
Here’s the text IN GREEK: καὶ εἰσελθὼν πρὸς αὐτὴν εἶπεν Χαῖρε, κεχαριτωμένη, ὁ κύριος μετὰ σοῦ. κεχαριτωμένη, is the pf. pass. ptcp. of χαριτόω (charitoō). It is the single Greek word kexaritomena and means highly favored, make accepted, make graceful, etc. REPEATED: It is a passive participle derived from charitoō. It does not mean "full of grace" or ‘completely filled with grace’ which is "plaras karitos" (plaras = full and karitos = Grace) in the Greek....
In contrast, the only one (though in some mss Stephen, in Acts 6:8) said to be full of grace is the Lord Jesus, "full ("plērēs) of grace (charis) and truth," using "plērēs," which denotes "full" 17 other places in the NT.
However, seeking to compel Scripture to support her tradition of men, Lk, 1:28 was wrongly rendered "full of grace" in the DRB, rather than "highly favored" or similar, as in Rome's current official New American Bible, “Hail, favored one!" (http://usccb.org/bible/luke/1) Yet the DRB translates Eph. 1:6 as "in which he hath graced us."
You may also argue that "Blessed art thou amongst women" supports the demigoddess stature of the Mary of Catholicism, due to her being most holy (rather than blessed due to whom she carried). But which logic also makes Jael an object of prayer to Heaven, as of her also is said, "Blessed above women shall Jael the wife of Heber the Kenite be, blessed shall she be above women in the tent." (Judges 5:24)
RCs argue that a sinless vessel is needed to bring forth a a sinless vessel, but which logic would require the parents of Mary to be sinless, while if instead Mary was somehow prevented from being stained by sin, as RCs hold (not Orthodox who do not subscribe to RC theology on Original sin), then the same intervention must be allowed for who Mary birthed.
Moreover, it was not necessary for the inspired writers who brought forth God's perfect word in Scripture to be sinless, proving that a clean thing can come thru an unclean instrument, by God's special working.
In addition, no where does the Holy Spirit state Mary was sinless, and yet the Holy Spirit characteristically mentions exceptions to the norm among notable persons, from great age (Methuselah), to excess size, fingers (Goliath), strength (Samson), devotion (Anna), diet (John the Baptist), and miracles when they are miracles.
Consistent with this, the sinlessness of the Lord Jesus is mentioned thrice. Therefore, as the Holy Spirit characteristically mentions exceptions to the norm, then unless He does then the norm is to be assumed. However, nothing is said of Mary being sinless. Nor among other things attributed to the Mary of Catholicism above that which is written, (cf. 1:Cor. 4:6) is being perpetual virgin in a unique marriage (leave but no cleave).
In the light of this lack of actual support, RCs attempt to argue from silence, that since the Bible does not say Mary sinned then it supports that she was sinless. Yet it does not say Paul sinned after conversion, and following the Romish principle at work here, since Scripture does not say Mary lived to be 160 like Abraham, and parted the Red Sea, and Jordon, kept the sun from going down, and had 12 fingers on each hand, and could slay a thousand men with a jawbone of a donkey, and caused a 3.5 year drought, made iron to swim, and cleansed lepers, raised the dead, was supernaturally transported, etc., then Rome could decree these as infallible truths as well.
Much more refutation here on claims made for the Mary of Catholicism
The Douay is just a slavish translation of the Vulgate. It was Jerome who rendered kecharitomene as "gratia plena".
:Isaiah ch 7 v 13Then Isaiah said, “Listen well, you royal family of David! You aren’t satisfied to exhaust my patience. You exhaust the patience of God as well! 14All right then, the Lord himself will choose the sign. Look! The virgin£ will conceive a child! She will give birth to a son and will call him Immanuel—‘God is with us.’ 15By the time this child is old enough to eat curds and honey, he will know enough to choose what is right and reject what is wrong. 16But before he knows right from wrong, the two kings you fear so much—the kings of Israel and Aram—will both be dead.
Was Mary without sin? Let's read what Paul says about it.
Romans ch 3 23For all have sinned; all fall short of God’s glorious standard. 24Yet now God in his gracious kindness declares us not guilty. He has done this through Christ Jesus, who has freed us by taking away our sins. 25For God sent Jesus to take the punishment for our sins and to satisfy God’s anger against us. We are made right with God when we believe that Jesus shed his blood, sacrificing his life for us. God was being entirely fair and just when he did not punish those who sinned in former times. 26And he is entirely fair and just in this present time when he declares sinners to be right in his sight because they believe in Jesus. 27Can we boast, then, that we have done anything to be accepted by God? No, because our acquittal is not based on our good deeds. It is based on our faith. 28So we are made right with God through faith and not by obeying the law.
The importance of Mary in relation to The Gospel? In other words her position in the church? This seems pretty straight forward on the issue. Now that is not to say Jesus didn't love and look after Mary. He very obviously did love and care for her. He would even when on the cross.
Matt ch 12 v 46As Jesus was speaking to the crowd, his mother and brothers were outside, wanting to talk with him. 47Someone told Jesus, “Your mother and your brothers are outside, and they want to speak to you.” 48Jesus asked, “Who is my mother? Who are my brothers?” 49Then he pointed to his disciples and said, “These are my mother and brothers. 50Anyone who does the will of my Father in heaven is my brother and sister and mother!”
At the cross Jesus looking down at His mother and disciples does a final act of compassion and then fulfills all righteousness. He made certain His mother was to be cared for and accepted by his disciples. In those time women especially widows did not fair well without someone to support them. As such they were at the mercy of others. The passage states plainly intent. Now if Mary was as exalted as the RCC claims would she not have authority over their first Pope Simon Peter as well? Hum! Mary was blessed in the sense she was chosen to conceive our and her Lord and Savior. Mary's place in heaven is not known as these things are not to be known by man this side of heaven. No doubt she has many, many rewards.
John ch 19 V Standing near the cross were Jesus’ mother, and his mother’s sister, Mary (the wife of Clopas), and Mary Magdalene. 26When Jesus saw his mother standing there beside the disciple he loved, he said to her, “Woman, he is your son.” 27And he said to this disciple, “She is your mother.” And from then on this disciple took her into his home.
John took care of Mary as he would his own mother. How some of these basic verses get so twisted into scenarios some churches make them it out to be absolutely amazes me.
Who's wife was Mary? She was Josephs because an angel of GOD told him to take her as his wife. Children after the birth of Christ? IMO not an impossibility if there were siblings they could have rejected him and abandoned Mary thus His concerns asking John to take her in. Scripture doesn't say one way or the other because the focus of Christ and the disciples was not on Mary but on salvation through Jesus Christ as it should be.