yes as you say , she accepted . And because of that things would have changed even though those long held things were deeply entrenched, she knew the way to go

and she did .
she became a part of the christian congregation
Mary was never part of the "Christian" congregation. Neither was Jesus for that matter. There was no such thing, until decades later, in fact, almost a century later.
Mary in her adult hood, might have belonged to the "Sect of the Nazarenes", a Jewish group outside of traditional Jewish faith and practices. Gentiles were still gentiles who happened to believe on Jesus' teachings and promise, but there was no melding of the two groups for quite a while.
As far as Mary goes, at 14 years of age, one does not know much about anything, except pregnancy before marriage was a death sentence.
Being betrothed and being impregnated by one other than one's spouse was a double death sentence.
Her world and all she might have believed in disappeared in a flash, once the "angel" announced what God intended for Mary.
Perhaps the only thing that could be said with any accuracy might be that Mary's belief in the awesome power of God, was greater than any pain man could possibly inflict upon her.
She simply accepted God's will for her (with a resignation, I'm certain). Then God followed up with "trust me", and she said she did. The rest is history (as they say).
As an aside, it wasn't "Jehovah" that spoke to Mary...it was an angel (a messanger), because Jehovah, cannot look upon a sinful human, but through his Son, who hadn't arrived yet corporially, to claim mankind as his own.
You really need to read your bible more, up close, not from a watch tower...lol