Very reasonable. So if I am understanding you correctly, the Catholic belief is that the IC awaited a "ripening," so to speak of the Jewish people -- which is similar to the Orthodox view. The main difference is that at that moment, God acted supernaturally to cause a conception (that of Mary) that was different from ordinary human conception, even though it was the result of a union of man and woman.
Something about this still bothers me -- it strikes me as having parallels to the Protestant view of the conception of Christ as a pure act of God's will (just backed up a generation), but I'll have to think about it before I commit to an observation to that effect.
Oh, no!
No!
Aah!
Free from original sin Mary freely chose just like Eve freely chose. To undo Eve she had to defeat her in the same field. Here's the question. The Angel says, -- Your son is going to be the King and reign forever. The Girl says, -- Hm, OK, deal. This is a free will response but this is a concupiscent response. We must know that Mary was free from a disordered desire when she agreed to cooperate with God, -- truly free.
Consider the Apostles, and Judas in particular. They, too, at one point were asked to follow the King, and freely agreed. But their free will was a product of concupiscent minds, so their cooperation was mixed with vanity and betrayal till the Pentecost regenerated eleven of them. Their story reflects the struggle Mary would have exhibited had she been marked with the same stain of Adam. But the gospel sets her apart from the Apostles in her behavior and her role. It is logical to say that her consent was different in kind to their consent.