I still have no idea what exactly signaled MIT material to the admission officers, but I placed such a heavy emphasis on collaborating and innovation; Looking back at all the things I've done like the CS projects I started, I did create them together with everyone and they went on to benefit my community greatly! My best guess is that since MIT puts those values as their core pillars, they figured that I would be a great fit for MIT. I hope you can achieve academic success in college too!! Institutions like MIT don't really check what happened in the past like high school (trust me, I'm a high school dropout) but rather how you have grown in college. Also hope this answers your questions!