Confidence is something that many people have trouble with. Often times there are two extremes, people either don't believe in themselves and have low confidence or they believe so much in themselves they think they can do no wrong regardless of the evidence to the contrary.
But people will listen to and follow confidence even when the confident person is completely clueless on what they are doing.
I think though at most people who read these are more on the lacking confidence though not incompetent. Writers and artist tend to bounce between the extremes. I want you to realize that by writing stories, finishing even short stories, or poems, or novels makes you more competent than you realize as finish something like that is hard. To do it well is harder.
So when you know something or do something do it with all the unearned confidence of a mediocre white man. When you do not know something be wise enough to listen and learn.
Stay hydrated, keep dreaming.