Writing and Thinking

I have begun to write, but I have a hard time forgetting the quality part. I write sentences, then I stare at them for minutes on end. The form isn't right, the flow, the story. Does this matter to the plot? Do I need to talk about this? All problems that have plagued me before, but I suppose if I am going to make my goal, I really just need to get over it and write. I will write, and I will post it soon, but I think I am just nervous about people reading it. I haven't written like this before. So bear with me, be kind, and remember, comments are much appreciated, especially as I begin posting the story. Constructive criticism would be nice too.