Wash U is a great school, but it also ranks among the least economically and socially diverse of elite American colleges. Your background–rural Kentucky and, especially, first-generation college student–might therefore really appeal to the adcoms at Wash U who are looking to address the lack of diversity.
You also have a powerful backstory: Losing your mom at a young age (freshman in HS) is a devastating blow and a huge challenge. Your academic achievements and ECs need to be put in the context of that crucial backstory. Hopefully, your essay accomplishes this work of contextualization. Wash U should be left in no doubt that you are person who has overcome incredible personal challenges and who hails from a background that would bring a much-needed “alternative” point of view into the student body.
A lot will depend on your final ACT scores. If you can nail a 34, I think you have a strong chance of getting in ED. A 33 would also put you well in the frame. With a 31 or 32, you’re left hoping that your compelling background can make up for a score that is lower than ideal for Wash U (a school that particularly values strong test scores).
My advice to you would be twofold: Continue to work like crazy on prepping for the ACT, and don’t be afraid to take it more than once if your initial results are not good; hone the essay so that it paints a clear picture of the unique perspective that you would bring to the table as a Wash U student, a perspective that includes understanding the realities of human loss and suffering. Good luck!