I’m sorry @whateversquared, but most of that advice is incorrect. I doubt the OP is still checking this thread, but I can’t stand to have blatantly wrong information on here if other people come to reference it later. Literally no one expects a high school senior to know exactly what they want to study, or necessarily to have any substantial extracurricular activities related to their major. Include the ECs that best represent you as a person. NYU wants to see who you actually are, not some meticulously curated version of yourself.
PS - I applied as a psych major, and the only thing even remotely related to psych in my application was the fact that I took AP psych. My application and extracurriculars were diffuse. I was involved in generic volunteering, language tutoring, languages in general, music, marching band, and theater, none of which were related to psych.
Also, all NYU scholarships (with the exception of MLK Scholars and one other major scholarship) are need based with a little bit of merit thrown in (if you have need and high stats, you’ll get more aid that someone with need and lower stats). So if you don’t have financial need, it doesn’t matter how good you are, you are unlikely to get any money.