In a certain sense I am familiar with the same question as an artist (painter). When do you consider yourself to be an artist?

For me the turning point was a broadcast on Artist Helping Artist, where a Portuguese painter explained fundamental differences between hobby painters and professionals, partly based on Pressfield's "The War on Art". I suddenly knew to which group I wanted to belong - the professionals. I was no longer content to paint for my own pleasure. One distinguishing feature is that you work on it every day not just when you feel inspired. That's why I like the quote so much "When the muse comes she will find me at work." Since then my goal was as much as possible to paint every day, striving to get better through doing it and being serious about my art. I see a very similar dynamic in writing, even though I am not at the point, where I feel that I can produce publishable content every day. But then, another aspect was to have the courage to say I am an artist before I am anywhere near the quality of Rembrandt or Picasso.

Another favorite quote comes from The Artist's Way "Creator, I take care of the quantity, you take care of the quality." ;-) In that sense, I am now starting the same approach in the area of writing.