Given that so little of the Bible deals directly with Mary and given that the Bible itself states that it does not contain the stories of everything that Jesus did, the only logical conclusion is that the "pertinent information about Mary" is found elsewhere.
Just on such example would be Saint Ignatius' letter to her and her subsequent response, which can be read on this site as well as others. Here is where we can come to understand her ongoing role in the church.
Your initial statement cannot be supported by fact, logic or reason.
The key is ‘pertinent’. Sure there is more information, but how pertinent is it, and if it was so pertinent, why was it not part of the gospel? What most non-Catholics find odd about Catholics is more than half of the Church’s writings, art, worship centers around Mary. It is completely out of balance with scriptures. Mary is one of the most blessed figures of the Bible, but she is not our Savior.
Given that the bible is written by the Holy Spirit the only logical conclusion is that there is no other pertinent information that pertains to doctrine, reproof, correction and instruction in righteousness.
2 Timothy 3:16 All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness,
Your initial statement cannot be supported by fact, logic or reason.
That is true - - - - concerning your statement.