The bad part is that I'm probably talking to def ears. It's OK, I do realize everyone has to forge their own path in life.
The good news is that it is probably much less important than most people think. Very few people actually end up in their dream job and keep their whole life.
It starts with knowing who you are. For some people that's an easy question to answer. For the rest of us, not so much. Fortunately, there is plenty of help to get.
It might even be possible that some of us go about this backwards. In the old days, sons and daughters were much more likely to choose the same occupation their parents did, learning the trade directly from them.
There were fewer choices back then and the task of choosing a career was pretty easy. In many respects it was chosen for you. All you had to do was learn to be happy with it.
Most people have at least some level of natural curiosity and automatically become interested in what life makes them do. For those people opportunity is a major factor in forging their career path.