Destiny

I was only 14th years old when my family had a discussion about the meaning of destiny. There were three ideas about what could be the meaning of "destiny". The first one explains that the destiny is something that exist and people aren't be able to change. The second one establishes that is the human being who makes its destiny, and the final one considers that the destiny is a kind of guide in which the human being has certain degree of liberty to act. Also, this kind of guide is given by God.
I think, the destiny of a being is the collection of events that happen and influence the being during its existence. People want to control destiny all the time but life is too complicated to get that. Controlling the destiny means to know what will happen. In that sense the second position doesn't has a good support. But it doesn't mean that in the future we would know the way to decide our destiny. Today seems impossible, however, it depends on our own development and knowledge. It's the same when in the past people didn't believed that earth was like an sphere.
In the last 100 years the advances in different branchs of knowledge have increased dramatically. It's difficult (but not impossible) to predict how would be the world in 20 years.
Can you imaging that?