Mary and Joseph were Jewish. They would have had Jesus circumsized on the 8th day after His birth. Though Mary is an integral part of bringing God Incarnate into the world, caring for Him, raising Him, it is Jesus who fulfilled the Old Covenant and created the New Covenant. In Him and through Him.
He began His ministry first by being baptized, and teaching baptism as the initiation into the Kingdom of God. Why wait until then? All things are done in God’s time. Why wait 100 or 500 or 2000 years? Only God knows.
Jesus Himself did not require baptism to enter the Kingdom of Heaven. He was free from sin and is God, who brings us to Him by showing us the Way and giving us the graces found in the Sacraments.
Sacred Tradition, what is written and passed on orally, has existed since Jesus taught the Apostles, and they in turn taught others, and so on and so forth. The knowledge of all that Christ gave us is entrusted to His Church, beginning with Peter, and the other Apostles. Jesus guides His Church, through the power of the Holy Spirit, that He gave to the Apostles and the Church at Pentacost.
The OT used by the early Christians, was that in wide circulation at the time in Jerusalem. The Septuagint. It was a Greek translation of the Hebrew scriptures. The NT began as writings of the Apostles, and those who followed them. Tradition states, that as the Apostles began to be killed, and Jesus had not yet returned (as His followers believed He would before their deaths), the Apostles and others wrote the teachings of Jesus Christ down. The perfect interpretation comes from Christ’s Church, what has been preserved and handed down for 2000 years.
The Early Church Fathers record that the four Gospels and the letters of Peter and Paul were in wide circulation among the bishops of the churches (as each apostolic see is referred to). Other early writing were in circulation as well, such as the didache and the letters of St. Clement.
In all the Church, there was one Gospel, one Apostolic teaching. As heresies arose, the bishops held councils to discuss and clarify doctrines that were in relationship to the particular heresy. What is known now as the Bible began to solidify with the Montanist heresy, which, was coming from a man and two women who were claiming to be prophet and prophetess. They were creating new scriptures, that were in opposition to what the Church had held and protected. The council of the time declared that no new scripture could be added to the Apostolic teachings, as, what Jesus had revealed, and what the Apostles taught, regarding our Salvation was and is perfect, and needs no further additions.
Always, there has been Tradition associated to the teachings of the Apostles. The liturgy, the maintaining of the leadership of the Church, the practices, the prayers, are all held by the Church as Sacred, but are not canonized in scripture.
To the translation, the Gospels and letters have long been translated into different languages. As they were circulated they were translated, as the needs of each church (see) were in many different languages.
The language in Rome was Latin, of course. St Jerome took the Greek Septuagint and the earliest writings he could find of the NT books and translated them into Latin. This is the roots of the Douay-Rhymes. The Latin Church used this translation, almost exclusively, until the 1960’s, when the reforms of Vatican II declared the Mass should be said in the language of the people. And, that translations of the Bible should also be made available in the language of the people.
If you read enough Catholic theoligcal writings, you will run into the phrase “retrieved from Tradition”. The practice of using the language of the people was retrieved from Tradition, as, this was the practice in the early church. It is why there are Latin, Greek, Syrica, etc. rites to begin with.
The American Bible that came from this change in practice, is the
New American Bible. You can read in the introductions the process of translation. Since St. Jerome’s time, there have been great advances in language translation. Also, the discovery of the Dead Sea scrolls provided another ancient source to compare to, providing additional means in preserving the original intent of the Apostolic writings.
To any other Bible transaltion, such as the King James, there is history of each one. King James decreed a Bible be translated into the language of the people. Which, falls in the time frame of Elizabethan English, the same language of Shakespear. You can google on the method of translation that was used for this Bible. Also, books that the Protestant reformers did not agree with were removed by the King’s church.
Hope that answers what you were asking.