When I was growing up there was a lot of talk about exams and achievements that were expected, and later on stuff about careers but nothing at all about vocation. No sense that I needed God in order to make sense of what I should be doing with my life. It's probably not surprising that I made a bit of a hash of things: Oh I got the academic laurels and had the glittering career all right, but I squandered more than a decade of my life living a life that was fairly spiritually empty, never sure what I should be doing, constantly trying to fill a God shaped hole, and looking in all the wrong places. I can only say that it's thanks to the workings of the Holy Spirit that I didn't continue barreling down the wrong path.
Clearly the Holy Spirit works in ways that we can not even begin to understand. A very holy priest friend of ours came from an unlikely background: one parent a lapsed Catholic, the other an atheist. The children brought up without even a cursory reference to God. Siblings all went into the hard sciences and are not believers, but the eldest became a priest. How? Briefly - a blinding flash of a conversion in his late teens, followed by a baptism and the sacraments. The atheist father said he'd accept his son becoming a Catholic "as long as you don't become a priest". Not many years later, the son entered the seminary and the rest is, as they say, history.
But this is really the exception to the rule. It's difficult to underestimate the importance of Catholic families who encourage their children to think about their vocation from an early age, so that those children can take on board the idea that God has a plan for each of us, and that our role in life is to try to discern what He wants us to do, and how He wants us to use the talents that we have been given. This applies to the married vocation as much as religious vocations. Thinking about the idea of "vocation" at all is, I think, a very Catholic thing; the idea that we need to discern what God wants us to do with our lives.
One common problem is that many people in their late teens and early twenties tend to take themselves very seriously (it goes with the territory, it's a phase), and if they haven't had a serious spiritual grounding, been given a good sense of perspective, can lose their way very easily in the mire of post-adolescent egotism and cargo-cult spirituality. If, on the other hand, we've understood from a young age that we have a role in God's plan, that we have God-given gifts, talents and skill that we need to use to their best potential in order to fulfill God's work, then we are handed a lifeline during the post-adolescent years.
So the family is crucial is vital in providing a perspective that counters that of Society, but the message needs to be imbibed at the breast so to speak, not introduced in adolescence. A child who knows from the time he can lisp his first prayers that God made him to know him, love him and serve him in this life and to be happy with him forever in the next will not find it incongruous at the age of seven or eight to start considering what God's plan for him might be. This groundwork means that the "conversation" is already open by the time that adolescence beckons.