In a recent writers' discussion about interview questions that catch you unprepared, the question, "What made you start writing?" seemed to stump several writers. Many couldn't remember why because they started writing at such an early age they couldn't recall when they started yet alone why.
For many, I'm sure it was the encouragement of a teacher during their schooling or a family member who advised them to write down something they found entertaining so they could share it. In later life, it might have been a friend saying something they did would make a great story thus the seed was planted. In any case, recognition of a worthiness of a person to write or a story to be told is the beginning. Then there are people like me.
What made me start writing? My writing usually starts with an idea that grows into characters, and those characters start interacting in my head. The jerks won't shut up until I get them on paper. They keep me awake at all hours of the night. He should do this, or she should do that. Until, I work on the story to finish and flush them out of my head for other ideas, their name is legion for they're many, to possess my thoughts.
So, the quick answer is to stop the voices in my head.