What is Destiny?

Destiny is not "something we do not have control of".

Destiny is a sequence of opportunities (and, alas, challenges) that is given to every human being through the course of his or her life. What you do with those, which ones you grab, which ones you pass, what you endure and where you fail - is entirely up to you.

You should think of the opportunities and challenges that the destiny gives you like paths and barriers on an endless field. How you walk the field is up to you. You can take an easy path or cut a new way, you can halt at a barrier or jump over it (sometimes just bypass) - but they do not determine your journey, your choices do. So in effect - destiny is something you actually have absolute control of: these are your choices that shape it.