Protoevangelium and the Fullness of Time

My Self study Lesson #3 Protoevangelium and the Fullness of Time
http://www.catholicbook.com/AgredaCD/MyCatholicFaith/mcfc027.htm
I am quite a slow learner. But still, I think I have managed to comprehend ( slightly, perhaps!) certain mysteries which the Church teaches. 
First of all I understand that "Proto-evangelium"(First Gospel)  is a term applied to Genesis 3:15 -the promise of a Redeemer after the Fall.It is the first reference to the idea of a Messiah - Christ, Redeemer - in the Scripture. "And I will put enmity between you and the woman, and between your seed and her seed; He shall bruise you on the head, and you shall bruise him on the heel." 

"chaire Kecharitomene" - Rejoice Full of Grace....


Now let me come to "the fullness of time" , ie. the time when this 
Word , the promise of Almighty God "happens". From Eternity,  the Timeless Word enters into the time of this world. Pope John Paul II has explained this in his 'Redomptoris Mater'. I'll better quote:

 This "fullness" indicates the moment fixed from all eternity when the Father sent his Son "that whoever believes in him should not perish but have eternal life" (Jn. 3:16). It denotes the blessed moment when the Word that "was with God...became flesh and dwelt among us" (Jn. 1:1, 14), and made himself our brother. It marks the moment when the Holy Spirit, who had already infused the fullness of grace into Mary of Nazareth, formed in her virginal womb the human nature of Christ. This "fullness" marks the moment when, with the entrance of the eternal into time, time itself is redeemed, and being filled with the mystery of Christ becomes definitively "salvation time." Finally, this "fullness" designates the hidden beginning of the Church's journey. In the liturgy the Church salutes Mary of Nazareth as the Church's own beginning, for in the event of the Immaculate Conception the Church sees projected, and anticipated in her most noble member, the saving grace of Easter. And above all, in the Incarnation she encounters Christ and Mary indissolubly joined: he who is the Church's Lord and Head and she who, uttering the first fiat of the New Covenant, prefigures the Church's condition as spouse and mother.

 As the Second Vatican Council says, "she is already prophetically foreshadowed in that promise made to our first parents after their fall into sin"-according to the Book of Genesis (cf. 3:15). "Likewise she is the Virgin who is to conceive and bear a son, whose name will be called Emmanuel"- according to the words of Isaiah (cf. 7:14). In this way the Old Testament prepares that "fullness of time" when God "sent forth his Son, born of woman...so that we might receive adoption as sons." The coming into the world of the Son of God is an event recorded in the first chapters of the Gospels according to Luke and Matthew.

 Redemptoris Mater
(Latin: Mother of the Redeemer)
Encyclical Letter of Pope John Paul II

Redemptoris Mater (Latin: Mother of the Redeemer) is the title of a Mariological encyclical by Pope John Paul II, delivered on March 25, 1987 in Saint Peter's Basilica in Rome.

This encyclical is subtitled On the Blessed Virgin Mary in the life of the Pilgrim Church and deals with a number of issues in Mariology. It is a somewhat detailed encyclical with three main parts, as well as an introductory section and a conclusions section. http://en.wikipedia.org/wiki/Redemptoris_Mater