For the record, 2Timothy 3:16&17 is the compiled written source for us today, and also the Holy Ghost who lead us to the full truth from it,We must remember that Matthew and Luke got the birth of Jesus story from the only source, Mary. So, all this is from the memory of Mary. Matthew definitely knew Mary as the disciples and Jesus's earth family traveled together. Both left out conspicuous details that God wanted not to be revealed, like Jesus birth day, that a Mother never forgets.
That's a false gospel you're referrimg to and is not welcomed in this Bible Study Forum.
Only the 12 men including Matthew are the personally chosen disciples of Jesus and GOD, besides others are disciples on their own, and we have account on many of them stop following Jesus.
And before Jesus' ascensiion, He commissioned only the 11 as Apostles to take His discipled Gospel to the ends of the earth, and later Apostle Paul for further clarification to the Gospel.