Heading Subtopic scripture/quote body content

I have been working on a novel, and I've gone around four chapters in. I keep re-reading the first chapters, and I am tempted to edit them. Should I wait until I at least have a finished first draft to start editing, or should I edit as I go?

I have been asked to write a report on the company I am working at during a placement from University (I am on an engineering programme). There was not much guidance given on what the content of the report is supposed to be, this is what I've been told: First Report – this is informally known...