Don’t let fear of the blank page scare you from telling a story the world needs to hear.
Don’t let the story itself scare you.
Don’t let the process of writing keep you from writing.
What are people going to think of me if I tell this story? How am I going to fill these pages for a complete book? Where will I find the time? Will people even want to hear my story? How will I find an agent? Who will buy my script?
None of the above is your concern. Write anyway! Your focus needs to be on getting the story out of you, by any means necessary. The rest will take care of itself.