Here are a few scriptures as it pertains to "not knowing Mary UNTILL Jesus was born"...
Acts 23:12 And when it was day, certain of the Jews banded together, and bound themselves under a curse, saying that they would neither eat nor drink
till(G2193) they had killed Paul.
1 Corinthians 16:8 But I will tarry at Ephesus
until(G2193) Pentecost.
John 9:18 But the Jews did not believe concerning him, that he had been blind, and received his sight,
until(G2193) they called the parents of him that had received his sight.
Matthew 1:24 Then Joseph being raised from sleep did as the angel of the Lord had bidden him, and took unto him his wife:
Matthew 1:25 And knew her not
till(G2193) she had brought forth her firstborn son: and he called his name JESUS.