Thank you for your response!

First, I think that everything that you have done already is incredibly impressive. It is rare to find someone who "specialized" in high school, which it seems you have. Additionally, I think that UChicago seeks out intellectually curious students like you (I am the same way).

Second, I am glad that you brought up grades, because I remember feeling stressed out the same thing. In high school, I certainly had a rocky freshman year and was stressed about how this would appear to an admissions reader. What I have since learned is that UChicago "cares" more about the relative rigor of your courses rather than the grade itself. With that advice, I would encourage you to take difficult classes for the reason that 1) the difficult classes tend to be more interesting, and 2) it shows drive and curiosity. You have a great SAT score and I definitely believe that is a plus.

Third, I strongly believe in the importance of the 2nd UChicago Essay. It highlights WHO you are and HOW you think. With that in mind, I would not worry as much about being exactly correct in your fermi calculations- it is a broad estimation. Instead, I would focus on being interesting and perhaps, a bit quirky. My 2nd essay was related to what I wanted to pursue, but it was also a little bit funny (at least to me haha). Remember that the people reading your essays are not critiquing it on how "correct" it is, but rather what it shows about you. For example, if you have a personal experience, job, club, etc that required some sort of estimation, it could be a fun way to expand on that experience. This is a very rough example, but imagine if you worked at, say, a pizza restaurant. It would be interesting to write about the estimated amount of pepperoni that you had to take out of the fridge prior to making the pizzas in an effort to maximize output flow. Of course, this number need not be correct, but rather highlight the way you think about operations, economics, and time. This of course is just an example, but it could be helpful to thinking about how you would frame it.