Protestants go ape when we assert that Mary was "full of grace" and sinless, because of the "full dose" she received from God. You are virtually claiming the same thing for yourself and all bornagains. You all may appear to sin, but not really because no guilt is imputed to you. Nice gig if you can get it.
Whether you know it or not, you've stumbled upon the reason why Pope Blessed Pius IX thought it was opportune to infallibly declare the Immaculate Conception of the Blessed Virgin Mary as "a doctrine revealed by God and therefore to be believed firmly and constantly by all the faithful" (Ineffabilis Deus).
Yes it is a nice gig...
You apparently missed it...Jesus Christ became sin, for us...And then he became the sacrifice...And his rightousness was imputed to us...
Apparently your teachers have not taught you about the Spiritual Circumcision or you would understand this...
The only points of contention, I observe by Protestants of Marion theology, is the change in meanings from the following progression:
Mary is the mother of Jesus.
Jesus is God, the Son.
Mary is the mother of God, the Son.
This logic has a slight change in meaning of the object.
For example one could also make the argument (which is false for the point of reductio ad absurdum):
Mary is the mother of God.
God, the Father is God.
Mary is the Mother of God, the Father.
There are also other awkward implications from simple logic, which fail to adequately address Mary's relationship to God.
For example (another set of false conclusions):
Mary was full of grace.
Full of grace is being without sin.
Mary was never with sin.
Mary was a Perfect human.
The second Eve preceded the second Adam.
Mary is more exalted than Jesus Christ.
IMHO, to keep things at first simple, it is sufficient to state Mary is the physical mother of Jesus. Then allow doctrine to flow accordingly.
IMHO, on topical matters where not that much information is provided in Scripture, the issues on that topic aren't as significant in God's Plan for us as other doctrines. The relationship of Mary to Christ falls in that domain, IMHO.