The extravagant language of devotional works, as Robby notes, is not to be put on the same level as the Catechism or doctrine. But there is a sound reason for the existence of such works, especially in light of what Lewis calls "the discarded image" - the medieval and Renaissance worldview.
That worldview was different from ours in some fundamental ways. One was the concept of courtly love -- the devotion to a woman, ordinarily a noble, well-born lady, as an ideal to be admired and served from afar or below. Not out of self-interest, not out of any sexual element, but because part of the duty of a 'parfit gentil knight' was to treat women - of high or low degree - with respect and honor. The Blessed Virgin, as the woman of highest degree, was due the greatest respect and honor, and the most warm-hearted and devoted service.
This gave rise to an entire school of poetry and echoed down literature to Shakespeare and beyond. You see faint echoes of this not only in the homage paid to royalty, and in the devotion of an old-fashioned sort of man to his mother, but also in the traditional courtship where a young man speaks to his beloved in terms both extravagant and courtly.
He isn't really going to 'climb the highest mountain and swim the raging seas' for his young lady, nor are her eyes really like stars or her voice like music, nor is she lovely as the dawn, nor a goddess, nor does he in plain cold fact worship the ground on which she walks. But he says all these things, as an imperfect expression of his love and devotion. Nobody claims that on account of these facially false and outlandish statements that he is a heathen or a heretic, nor that he has put his beloved before God.
Bearing in mind this, bearing in mind also that the Church is slow to change because she is very old, and that men like St. Louis de Montfort (author of possibly the most popular devotion to Mary) were schooled in the old traditions of courtly devotion, perhaps you can better understand some of these expressions.
Some might think that the cold wind that blew through Geneva and Edinburgh and swept away the warm-hearted and pure devotion of gentlemen to the ideal of a great lady was a bad thing, at least in that respect.