Gabriel speaks to Mary is Luke 1:28, "Hail, you that are highly favored, the Lord is with you: blessed are you among women."
In other words she hold an exalted place in God's heart and He has blessed her among women. Hence first among saints (or women).
Jesus would have shown her a special honor since she was His mother, and so I see no reason why we should not either.
Just like a King's mother is not the King, we don't submit to her, but just as insulting the King's mother is as bad, if not worse, than insulting the King, that is how I feel we should treat Mary, as the blessed mother of our King.