In brief, Vatican II was a meeting of all the Catholic Bishops (with lay observers, theologians and members of other Christian denominations present). It's purpose was to renew the Catholic church and update it to be relevant to the modern world. Some examples of its sweeping changes were mass in the vernacular (i.e. English instead of Latin), and a larger recognition of lay people's roles and vocations in the church.
Although we got a bit side-tracked by cultural/political issues in the wake of Vatican II (i.e. did these sweeping changes go too far? Are we experiencing a backlash, etc.) I only wanted to point out that the Church in the world and the People of God are also creatures of history. The church we live in now, Post-Vatican II, is very different than before Vatican II. At the same time, there are many changes that still are ahead, some of which we may not even be able to envision. For example, we have far less priests and nuns than before. So the Church which you are preparing to join as you become fully Catholic is a Church in which you need to be aware of such differences and changes.
Similar to our analogy of moving from dating, to engagement, to wedding and beyond, your relationship to the church is not a static goal that upon entry everything stops and stays the same. Rather, you should realize that you will be part of a dynamic and changing church that will always to one degree or another strive to be relevant in the world.