This still feels like plot summary. I'm not sure where you are with the assignment, but how you finally "let it go" needs to be described in order for the premise to matter at all. If it was so easy to let go of, then why not let go sooner, for example. Also, you begin to tell your reader a little bit about Burning Man, radical self-reliance, but you don't really work this into your story. What are the other two themes? Back up and explain the festival, give context, so that we recognize the size of the crowd and how it arises out of nothing (the desert), before you give the actual number. Let us feel the scene more intensely. Many possibilities here. Think of you and your father and your friend as characters in your story, and introduce accordingly.