Ray Bradbury said, "Write a short story every week. It’s not possible to write 52 bad short stories in a row."And Ernest Hemingway said, "The first draft of anything is #%!@." (I modified that quote a little.)
We, as writers, can be our worst critic. Often we are afraid to start or continue writing because we expect a lot from ourselves. And I say we should expect a lot from ourselves, but just give the first draft a break, give yourself freedom to just write without the critic looming over your shoulder.
I like to imagine that when I'm gone and the only things left behind is my name on a tombstone and the memories of me from the ones who knew me, that I will have also left behind piles and piles of writings, whether masterpieces or scribbles, that will speak for who I was and how I never quit writing, thus telling the world: I was a writer.
So, write something, then if it's terrible, keep writing. Write something, then if it's wonderful, keep writing. And remember, there is always editing after writing.