I think with NYSMMA, the score matters, not just the level. Were you, based on your score, ever nominated to represent your school in one of the honorary groups (county level)?
For context, my child is your age, and has participated in NYSSMA (Level 1 & 2 perfect scores, Level 4 24 out of 28). And was in her school’s Chamber Orchestra (by audition), in addition to the regular school orchestra. This is not considered super accomplished by private school standards.
My child also has been dancing for 10 years, 7 of ballet - well, until Covid forced the dance studio to close forever. (I was looking forward to see her perform en pointe to The Magic Flute. 
) Again, not exceptional be private school standards, maybe well rounded. How impressive your dancing is depends on the kind of dance, and level.
Girl Scouts: the Silver Award can be a tremendous accomplishment, or “oh well”. Be sure to be able to talk up what you did. Some Silver Award projects are more girl-led than others, and hopefully your project was one of those that were more girl-led. Talk it up if this was your project that you came up with and put into action. The Silver Award is only impressive if you did it and can describe what you did.
I am only addressing the ECs that I know something about.
(My child did not consider applying to any of these schools. Perhaps we have an inferiority complex.)
Your chances will be based on how you present yourself. Emphasize your strengths, and how you’re an interesting well rounded person, while avoiding being obnoxious. (It’s a delicate balance.)
Do not mention your IQ.
Do make sure your essays are interesting and well written.
And please, cast a wider net than these 3 schools!