Start with a short story! The first steps you outlined are great.
Assuming this is your first step into the world of published works, I would highly recommend starting withyou consider a short story, perhaps leveraging some of your characters and that leverages key elements ofand characters in your outline as as your next progressive step towards the world/environment you are creatingeventual full novel.
A few reasons why:
It's semi-instant gratification - it gets people engaged and reading your work much earlier. That type of feedback is incredibly useful for a new writer. It can help you refine the key elements that will be the building blocks of the full novel you envision.
It challenges you to be compelling and make everything you write count. Great short stories can be as short as 1,000 words. One of my favorite Ray Bradbury stories is only 1,444 words long, but it is amazing! That skill development will be important as you then undertake the full novel development.
It getshelps you out indevelop the world ofskills associated with self-publishing and promotion! That does wonders for building up the commitment it takes Those skills are important to write abuild awareness of your novel.
Best of luck!