Think this isn't an important question? Well, think again!
Some people envision writing as an easy path to fame and fortune. "Look out Jane Austin and J.K. Rowling! Make way for (insert name here)."
Others want to make a living doing what they love. "I love to write. I write all the time. Wouldn't it be great to get paid to do something I'm doing already for free?"
Then there are those who feel that they don't have anything else to do. "I lost my job; what else am I going to do but write?" Or... "I'm graduating from high school in four months, I need to find a way to make a living." Or... "My kids are grown up, and I need a hobby. Writing seems like a good idea."
Understanding why you want to become a writer (and, possibly, an author) is an important first step because your motivation will impact your goals, your habits and your outlook.