To me, "Getting Started" means "in the day" or "in the project." Example: for every single book, Terry Pratchett, Margaret Atwood, and Michael Chrichton had to get started. Maybe it's from random notes and beginning to turn things into a plot, maybe it's opening a new file and typing, maybe it's doing pre-writing, or arranging for someone to transcribe the dictation.
Also, every day that they wrote (whether it was truly a daily thing or whatever their work habits were), they had to also get started. It may be about tea and a new pen, or rereading the previous writing, or setting a timer -- whatever ritual or procedure indicates Writing Now.
But as far as becoming a writer, they only were beginners early on. While "Getting Started" might refer to a career-phase, I feel that other tags (such as "first book" "first-time-author" or even "beginner") match that more. I don't feel that Getting Started is a great synonym for Beginner.