you're avoiding the question ... you're trying to ascribe 100% infallability when this teaching is clearly wrong to anyone who has read the Bible ...
now Mary is either the "mother of God" or she isn't ... I'd be interested if you'd be willing to make public your stance on this issue ...
It is clear from the link I posted to you where my position is. But as I said, Newman being the intellectual giant that he is lays it out far better then I could. Perhaps some time you could look it over objectively and then address it.
As for scripture, you have stated that your authority for interpretation is yourself, which as you stated rejects marian dogma. I myself will stick to the authority of Rome in this matter.