We commonly do not remember that it is, after all, always the first person that is speaking. I should not talk so much about myself if there were anybody else whom I knew as well. Unfortunately, I am confined to this theme by the narrowness of my experience. Moreover, I, on my side, require of every writer, first or last, a simple and sincere account of his own life, and not merely what he has heard of other men's lives; some such account as he would send to his kindred from a distant land; for if he has lived sincerely, it must have been in a distant land to me.
~Henry David Thoreau, Walden
It is nigh about impossible to write any sort of convincing essay about something you know little about, which is the main reason why so few of us read essays for pleasure--we sense the fraud and deceit of the writer's argument, and so we turn away from the writing piece like we would a piece of cheese gone bad. Still, as teachers, we fire away on the front against an overwhelming army, thinking we can win a battle that is lost from the start; we expect you to know, and if you don't know, we want you to figure out a way to make it sound like you know. This goes on from middle school through college--and then you graduate, and ninety percent of you will never write a true essay again (thank God for the ten percent) because you never will have written a true essay from the start. To write a true essay you must begin from the ground you know well. Thoreau knew this and admonished every would be writer to start from this unflinching ground of oneself: "Moreover, I, on my side, require of every writer, first or last, a simple and sincere account of his own life, and not merely what he has heard of other men's lives." [Economy: Walden] This is the spirit you must embrace in this essay when you explore this question: "What did the first chapter of Walden offer you, and what did you take away?"
Sometimes it is best to start with what you don't know, and since you are writing about Thoreau at a fairly young age, you probably don't know enough about his tome of writings to overly praise or condemn him; you probably don't get all the complexities and nuances of his arguments in what you have read, so if you decide to attempt a strict literary analysis, you run the risk of sounding uniformed at best and arrogant at worst--but don't let this dissuade you from writing about Thoreau! This doesn't mean you have not had a profound and transformative literary experience; it does not mean that your thoughts, insights, and opinions are not as valid as those of the most seasoned critic. It simply means that a narrative essay--since its genesis is in the undeniable validity of you--is probably your best approach to writing about your experience reading and reflecting on the first chapter of Walden--that maddening treasure trove of pithy wisdom and parables simply called, "Economy--"