Your own decisions are part of what makes up your life, but there are many things outside of your own control. Examples are pretty easy to find: Your place of birth, socioeconomic conditions, time period, and the many events throughout your life that were caused by other people. So yes, your decisions are involved, but there are many other factors
Why? It is the old debate in philosophy of objectivism vs determinism. Is there a rational basis for determinism? What about 'free will' or Nietzsche's 'will to power' To hold on to the idea of determinism, that would narrow the speculative world to one action, consistent with the laws of nature , therefore no allowing any other alternative explanations. Therefore, in this short analysis, I can only assert that free will and deterministic causality are a careful blend to one's life just as environment and nurturing is in development.
Though circumstances over which we have no control will occur often, our lives - whether good or bad - are a direct result of how we have responded to those situations. That is our choice. Circumstances don't define who we are, rather how we react to them. Linguists recognize statements as illogical if they are semantically incorrect. For example, "My friend made me have green eyes," is not a truthful statement, similarly, "My friend made me frustrated," is semantically identical and structurally incorrect. Our thoughts and feelings (negative and positive) directly impact who we become as people. And it is who we are, as a person, that determines the quality of our life.
One ship sails East,
And another West,
By the self-same winds that blow,
'Tis the set of the sails
And not the gales,
That tells the way we go.
Like the winds of the sea
Are the waves of time,
As we journey along through life,
'Tis the set of the soul,
That determines the goal,
And not the calm or the strife.
-Ella Wheeler Wilcox
I did not decide for my dad to commit suicide. I did not decide for my mom to put us in foster homes. I did not decide to be in a foster home where the woman did not know about the germs on cutting boards so that my sisters threw up ON the dinner table EVERY night. I did not decide for my foster mother to laugh at me and tell me that, if I threw up, I'd have to clean that up too. I did not decide for my mom to stay in bed and be an ass because she is not a singing star ( as if any one cared ). I did decide that leaving home was worth it but no body told me about long-term employment and unfinished school. Any one who says that I made my own life the way it is, is welcome to step out side