Writers can spend a lot of time 'not writing', even though they have story ideas they are busting to work on. It seems outrageous to be raring to get writing and then, not. So why not?
A lot of the time it's because of fear.
Fear is sneaky. It skulks. It's also really good at pretending to be something else: I need more time. I have to do more research. I need to finish my outline first. All seemingly legitimate reasons for not writing; all just a cover story for a hidden fear.
What are your doubts? I'm not good enough. My ideas are crap. Nobody would want to read this anyway. I don't know how. This idea is too good to mess up. My characters are boring. My story is boring. I'm boring, waaaaah! It all comes down this: I'm not good enough, I'm not good enough, I'm not good enough.
I get on and write by reminding myself of two things:
1. All fear and every fear is really the fear that you aren't good enough.
2. It doesn't matter how good you are because nobody will write your story but you.
It doesn't matter because there isn't anbody better, there isn't anybody else who can do it, there is only you.
Actually writing your story doesn't depend on how good you are, it depends on how determined you are. And later, after it is written, then you can decide how good it is and what work needs to be done to improve it.
Write the story. You're the only one who can.