I think we have to believe that she is the Mother of God, since our Lord's own testimony proves He is God. Once when I was reading about the miracle of Cana it struck me full force that here God Himself has bowed to the whim of a woman. Wow, that is more than just respect for a parent!
[I liked this quote from post 35: She is the only person, human or divine, who could say to God the Father "Your son and mine."]
I have never remotely understood the Immaculate Conception; indeed I always thought it referred to the conception of Jesus and was amazed to learn it referred to Mary's conception. Since I believe that God hallowed all his creation (unglamorous though it may be at times) when He chose to be born of a woman, I do not find any necessity for Mary to have been without original sin or more than human. It seemed obvious to me that at the moment of conception Mary would be sanctified and purified in body and soul...how could it be otherwise with her union with the Holy Spirit and the Son? But with God all things are possible and he certainly COULD have prepared for an immaculate vessel ahead of time.
We are not surprised to know people who are devoted to St. Francis or to St. Benedict or to St. Paul but always a little bothered at those who are devoted to Mary. I have known a number of them in recent years and find they are primarily devoted to our Lord and view Mary as an intercessor to aid them in their prayer life. Most of us have grown up in a faith environment that really never discussed Mary. I remember many years ago when a rector, fresh out of seminary probably, preached a sermon on our need to look at Mary and appreciate her. You would have thought he had uttered profanity from the pulpit, so shocking it was to hear it. I thought the sermon was very good, right on target that we should come to know this very strong and fascinating female character who was the first called to serve the Lord in the New Covenant, to pay honor for her obedience and pity for her pain. There are good scriptural reasons for much of Marian doctrine but they are not clearly defined, as the Holy Trinity is not, but must be deduced from both the Old and New Testament allusions.
I continue in my personal prayers to address the Father, as Our Lord instructed, and to think of Christ as our only mediator and advocate. But since we believe that, especially in the Eucharist, our prayers are part of that great and continual stream of prayer that is always rising to join the praise and worship of those saints before the throne of God, I don't see how it could hurt to ask their assistance. I continue to wonder why the Fourth Century Church did not include this in our Creed if we were to be clear about it, but of course there are many faith issues not addressed in those ancient phrases.
I wondered for a while how a sinless Baby could be conceived (not merely stored in) a sinful womb. I postulated that perhaps Jesus' divinity was accomplished by John's baptism. It's possible, but it requires speculation, and it's all about denying what the Church teaches about Mary, which is probably the simplest and most obvious construction of the record.
In my "journey" back into the Church, I have seen one question after another answered, one doubt after another washed away. This has happened so often that I don't bother to doubt the 2000 year old Church any more.