The Truth About Gatsby

Gatsby tells everyone lies about his past because he is embarrassed to tell the truth. He tells lies because most people that have the amount of wealth he has come from more sophisticated background. He wasnt born wealth like Tom or even obtain his wealth in a legal way. 

Nick waits to tell us this information about Gatsby because, maybe, he wanted us to know the truth before something bad happens. This might be foreshadowing the death of Gatsby. Also, he wanted us to hear all the rumors about Gatsby so we would read on to find out who he actually is.