You have already gotten good advice from parents, some of who, like me, are alumni and have students currently in the school. No one can calculate your chance for being admitted to a school that has a less that 7% admit rate. Most students that apply have the same exact attributes you do. Please listen to the advice that your LOC’s, counselor recommendation, extra-curriculars that you can show are near and dear to your heart and a outstanding essay is what will help you stand out. I always focus on the essays. My advice is to keep your parents out of the process (parents will gasp here). Adult intervention in essay writing is obvious to AdComs and can be a kiss of death. Write an essay that comes from a place within you. Though people may say that there is no depth in 17 year olds, I absolutely disagree. Whether it is sports, helping out in your community, doing research, playing an instrument or whatever, there is something that is dear to you and that you can write passionately about. I read an essay about the lack of sleep of a swimmer and how they went through high school in a fog because of early morning practices - yet managed to excel in school. I am sure that stood out to the committee. She was admitted to her first choice. My daughter wrote about stuttering and how she overcame it via public speaking and competitions.
If you have not started writing your essay, do it now!! It is hard to be creative when you have schoolwork and other activities competing for your time. Begin it now in the summer so that you can work on it and tweak it over the next few months. Let an adult read it before you send it for grammatical errors and to let you know if it flows. They should not “correct” it or write it for you.
Good luck!!