While I’m sure you can think of good reasons to procrastinate, I very much doubt there’s much real merit in any of them. There is no need to wait for inspiration; no need to find your confidence; no need to know exactly why or what you’re writing; no need read wise and thoughtful books about how to write; no need to know your story; no need to understand your characters; no need to be sure you’re on the right track; no need even for your research to be complete.
No need now.
Later on, it will be very nice indeed to have some or all of these fine things. You will of course eventually want inspiration and confidence and self-knowledge and faith in your project and informed technique and a finished story with developed characters and completed competent research. But every single one of these things – even the research – comes to you only in the process of writing. They are the result of writing. If you let any one of them immobilize you before you write, I can guarantee that a year from now you will still be waiting to begin.