How long will it take for you to be an 'artist'?
Once you begin, you are!
You are practicing your craft, honing your skills, and learning the art of being creative. That is what an artist is. It is not waiting until you produce beautiful perfect pieces of work - that is the end result of a great deal of thoughtful deliberation, effort, and perseverance.
It is devotion to your art practice that makes you an artist - learning and growing creatively.
And mileage, mileage, mileage!