Your resume is not strong for these schools, no offense intended, but you are on a Chance Me thread.
You are missing a hook for athletics, the arts, awards, and community service (starting at an animal shelter in Oct as you are applying could be seen as a negative, TBH, as in resume filler).
You will need to hit a homerun with your interviews and SSATs. PRACTICE interviews with an adult. Google prep school interviews questions, not to memorize, but to be comfortable talking about yourself. Buy the SSAT.org prep materials and start scoring your initial efforts.
As I always write in these threads, you are going up against 2,000 perfect candidates for 300 seats. Countless class presidents, Student Council presidents, state awards winners, nationally ranked athletes, small business owners…and those efforts just get you into the “maybe” pile. No one in admissions is impressed with any accomplishment I just wrote. All baseline stuff, so to speak.
So your resume is not traditionally impressive. So for your hopes it is, What do you bring to the incoming class? What about YOU is the puzzle piece they are missing for next year? You are going to need to sell yourself as a person. An interesting, engaged person adding to the campus and class environment.
If you can answer that, you have a shot (with 90th percentile+ SSATs).
This is meant to be helpful, not insulting. Best of luck.