You are just showing us that when you read the Sacred Scriptures, you do not understand what is being said.
1. Jesus brethren. Brother-kin-cousin are all the same word in Aramaic. None of the passages used by ignorant exegetes ever prove anything other than Jesus had male relatives. Never is any man referred to as the son of Mary, except for St. John at the foot of the cross. Jesus’ final words to all of us are to accept Mary as our mother. Which is what faithful Catholics do.
2. Luke 1:34 specifically highlights her vow of virginity, which she did not want to break. If you think a perfect intellect, not clouded by original sin, would be asking about the birds-and-the-bees the instant before rendering the FIAT that would precipitate the Incarnation, your penetration of the mysteries swirling in Luke 1 is woefully shallow.
3. Isaiah has everything to do with perpetual virginity, he was talking about The Virgin. All of the sacred music written since that Fiat back me up. Bach, Mozart, Palestrina, Thomas Aquinas, we’re all buds. :)
4. Your rule of faith is your human interpretation of a sacred text you do not understand. My rule of faith is a gift from God, given in Baptism, by which I have the sensus fidelium when exposed to inspired text. In my case, faith precedes private interpretation, in your case private interpretation precedes faith. It is what St. Francis de Sales calls using reason as a positive rule of faith, when in reality it can only be used as a negative rule of Faith. Evidence for this is the thousands of protestant sects which all claim to have the Bible as their rule of faith. If the Bible is God-breathed, where is the division coming from, if not from the inverted use of reason as a positive rule of faith?
Apart from the FACT that the NT was written in GREEK, I ought to point out that Aramaic also has a word for cousin. Find an Aramaic lexicon and look it up.
As I pointed out, Luke used cousin (and kin) - he knew the words, he just didn’t use them when discussing the brothers of Jesus.
Also, as I pointed out, the NT never says X the brother of Y unless he is.
Nor did Mary plan on being a perpetual virgin in some sort of weird vow - “18 Now the birth of Jesus Christ was as follows: when His mother Mary had been betrothed to Joseph, before they came together she was found to be with child by the Holy Spirit. 19 And Joseph her husband, being a righteous man and not wanting to disgrace her, planned to send her away secretly. 20 But when he had considered this, behold, an angel of the Lord appeared to him in a dream, saying, “Joseph, son of David, do not be afraid to take Mary as your wife; for the Child who has been conceived in her is of the Holy Spirit.”
That is not a description of some sort of perpetual virginity vow, for Joseph planned on taking her as his wife, until he found out she was already pregnant.
But those facts don’t match your doctrine, so wish them away if you will. But please don’t pat yourself on the back, and claim to be a Christian and call me a heathen (”Your rule of faith is your human interpretation of a sacred text you do not understand. My rule of faith is a gift from God, given in Baptism”) when you use doctrine to determine what scripture says, instead of using scripture to determine what your doctrine should be.
Those who demote the word of God below the teachings of the men who run their church deserve any deception they fall in to...