“co” in Latin means “with”
Without Mary there would have been no birth of Jesus.
John 14:6 is quite clear, quoting Jesus: No one comes to the father except through me. Mary was chosen by God and deserves all the praise for her role as mother to our savior.
But there is zero Biblical basis for Mary as perpetual virgin and as a mediator between we humans and God.
Find me a verse and we'll keep talking. But I think you'll have trouble finding anything except Catholic tradition and the issuances of Catholic conferences dating back 1700 years.
Ditto for Peter as the first Pope, the doctrine of infallibility, and the fact that priests are holier than anyone else.
Don't get me wrong, I'm not anti-Catholic and I'm not one of those evangelical Christians who believes that Catholics aren't saved. I just don't subscribe to the claim from the Catholic Church that only by THEIR church can I be saved. And I have the Bible to back me up on that.