You are aware the Canon of Scripture is a matter of Tradition, specifically because the Church assembled it in 393.
The New Testament as we read today, was written AFTER the resurrection, and after the laying on of hands of Matthias.
The Church, ordained by Jesus Christ, was responsible for this definitive act, like those before it, as well as definitive teachings. One only need look at St. Ignatius of Antioch.
Teaching was done mostly by oral tradition. Jesus didn’t commit a word to paper. Rather, He left it to His Church to decide.
Consider those things.
And it 'decided' that a bunch of stuff SHOULD have been 'scripture' but somehow it wasn't included.
Therefore, Mary herself had to visit earth and get the data included.
I wish on one of her future trips she'll bring us some unicorns!