Who is this Nick Character? - Start of Great Gatsby

Having recently started The Great Gatsby by F. Scott Fitzgerald, a certain sentence sort of made me stumble.  "What you doing, Nick? (p. 10) I stopped and did a double-take, which is somewhat embarrassing because the sentence was quite simple.  At first I was thinking "Who is this Nick person?" but after taking advantage of the insane power of context clues, I quickly realized that Nick was the narrator.  I was simply confused as to why Fitzgerald waited 10 pages to reveal Nick's name, and only his first name at that.  I suppose it might be because Fitzgerald doesn't want us to have an attachment to the narrator and wants us to question the morality or logic of actions later in the book.  Although this somewhat seems to conflict with the advantages of  first-person narration.  Perhaps he just didn't think Nick's name was important.  I suppose his name has hardly value, if any, compared to his personality.  Overall I guess I am still confused.  I guess I will have to read on and see if the story explains Fitzgerald's delay.