Yoda: Do or do not. There is no try.
Yoda gives Luke this advice as he is training to become a Jedi on Dagobah. All Luke can see is how hard everything is, how impossible it all sounds.
Luke is defeating himself, quitting before he has a chance to really succeed.
Writing is much the same. If you have decided that writing is impossible, you will never even start. If you decide that you don’t have time to write, you will never find the time to write.
Each of us has the same 24 hours to work with. Even carving out a half an hour out of the day will, in time, see a novel in your hands. It may not even be a good novel. Write the next novel. And the next.
Luke: I don’t believe it.
Yoda: That is why you fail
Don’t let yourself fail. Keep writing.