I'm new to this forum, but hope my experience speaks to you. I quit my teaching (high school English) position a few years ago to become a full-time writer. While I've been writing all sorts of short stories and poems my whole life, I didn't know much about the industry itself. What I did know was that once I turned to writing fulltime, there was no "Plan B" for me...I was going to be a successful author. My goal was a bit different than most on this board - I wanted to write books. I wrote two novels and during the writing process I was also researching everything I could about the business end of the industry. I also wrote for a newsletter and a regional magazine to build "clips" and a platform of sorts.
Fast forward two years after changing careers and I landed a literary agent in NYC and a book deal with McGraw Hill (all happened a year ago and the book is due out early next year). What I didn't expect was to sell a nonfiction book rather than my novels (although those will follow). What I learned was "Be the Writer" and you'll be amazed at how things fall into place.
If you're interested, I have a lot of resources for aspiring writers on my website http://wwwheatherhummel.net
Coincidently, the book I wrote is about chasing your dreams no matter how old you are! I co-authored it with my mother, who is a 68 year old model.