Well what you where told is sort of true. The books of the New Testament where finished by around 90 AD. For the first few centuries there where quite a few more books that some accepted as Scriptural and others did not. There was the Gospel of Thomas, and various other Letters of Paul, Peter, James and other Apostles. The Gospel of Mary the Shepherd or Hermas, the Epistles of Clement (one of St. Peter’s successors in Rome) It was a couple of Centuries after Jesus death and resurrection that the Church was able to gather in Council and decide what books should be included in the Canon of Scripture, and which should not. While some books listed above where for one reason or another rejected as Inspired books, they do give us a peek into some of the beliefs, (both firmly Catholic, and heretical) that where floating around the Early Church.
The Council of Carthage pronounced on 28 August 397 issued a canon of the Bible restricted to: Genesis, Exodus, Leviticus, Numbers, Deuteronomy, Josue, Judges, Ruth, 4 books of Kingdoms, 2 books of Paralipomenon, Job, Psalter of David, 5 books of Solomon, 12 books of Prophets, Isaias, Jeremias, Daniel, Ezechiel, Tobias, Judith, Esther, 2 books of Esdras, 2 books of Machabees, and in the New Testament: 4 books of Gospels, 1 book of Acts of the Apostles, 13 letters of the Apostle Paul, 1 of him to the Hebrews, 2 of Peter, 3 of John, 1 of James, 1 of Jude, and the Apocalypse of John.
Many Protestants rejected some of the Old Testament books, and even wanted to reject the Epistle of James from the New Testament, as they contained teachings that they did not like. They claimed that the Hebrew Bible did not contain some of the Books that Carthage had decided to incorporate into the Canon. What they fail to take into account is that the Jewish Canon was not finalized until after 600 AD and it was primarily in reaction to the Rabbi’s who where upset that Christians where claiming to prove the Messiahship of Jesus in part by using the Jewish Scriptures. The Jewish Canon accepted only those books originally written in Hebrew, and rejected those written in Aramaic and Greek. Today you will see some Protestant books and websites claim that the Catholic Church “Added” books to the Bible at the Council of Trent. The fact is the Books “Added” at the Council of Trent, really did not get added, but the Council simply affirmed that all the books which had been decided on at Carthage where Scripture, after the Protestants and Jews had removed them from the Canon.