St. Jerome’s Latin Vulgate translation of Genesis3:15 is superior to all biblical translation as it was approved by Church Magisterium, and Church Magisterium under the Pope is guided by the Holy Spirit the Spirit of Truth, they cannot err in judgement and teaching with regards to faith and morals.
Douay-Rheims 1899 American Edition
12 I have yet many things to say to you: but you cannot bear them now.
13 But when he, the Spirit of truth, is come, he will teach you all truth. For he shall not speak of himself; but what things soever he shall hear, he shall speak; and the things that are to come, he shall shew you.
14 He shall glorify me; because he shall receive of mine, and shall shew it to you.
Here are the words of Pope Benedict XV on St. Jerome, upholding his great contribution to the Church, and the Catholic Church reveres him as the "Greatest Doctor".
SPIRITUS PARACLITUS (On St. Jerome)
Pope Benedict XV
Encyclical of Pope Benedict XV promulgated on 15 September 1920
To all the Patriarchs, Primates, Archbishops, Bishops, and Ordinaries in Union with the Apostolic See.
Since the Holy Spirit, the Comforter, had bestowed the Scriptures on the human race for their instruction in Divine things, He also raised up in successive ages saintly and learned men whose task it should be to develop that treasure and so provide for the faithful plenteous "consolation from the Scriptures."*** Foremost among these teachers stands St. Jerome. Him the Catholic Church acclaims and reveres as her "Greatest Doctor," divinely given her for the understanding of the Bible.*** And now that the fifteenth centenary of his death is approaching we would not willingly let pass so favorable an opportunity of addressing you on the debt we owe him. For the responsibility of our Apostolic office impels us to set before you his wonderful example and so promote the study of Holy Scripture in accordance with the teaching of our predecessors, Leo XIII and Pius X, which we desire to apply more precisely still to the present needs of the Church. For St. Jerome - "strenuous Catholic, learned in the Scriptures," "teacher of Catholics," "model of virtue, world's teacher" - has by his earnest and illuminative defense of Catholic doctrine on Holy Scripture left us most precious instructions. These we propose to set before you and so promote among the children of the Church, and especially among the clergy, assiduous and reverent study of the Bible.
Why St. Jerome translated Genesis3:15 as "She" carries the oral Tradition of the Church with regards to the role of Mary, whom the early Church Fathers like St. Ireneaus, St. Justin Martyr, St. John Chrysostom play a special role in the salvation of man.
What the Early Church Believed: Mary is the Mother of God
But, the most clear explanation why Genesis 3:15 must be a "She" and not "He or Jesus" can be seen At the Foot of the Cross. Jesus defeated Satan but did not crush him, as Satan still vey much active after Jesus resurrection.
In Catholicsm and in Mary's approved apparition, the Catholic Church approved Fatima apparition which claimed the victory of Mary the chosen Woman over Satan with these concluding words...
"In the end my Immaculate Heart will triumph". - Fatima message.