I note that the student sign-up uses zip-code to try and classify low-income students. I live in the low-income part of a rich city (Menlo Park), and the whole city just has one zip code. This would exclude a lot of the low-income students who live in my neighborhood. I used to be a volunteer tutor with the local boys and girls clubs of America (bgca.org) chapter and the students who would attend there were exactly the demographic you’re targeting. I know you partner with some schools, but you might want to also consider using organizations like bgca as an alternative way of identifying these kids. You probably don’t want to go to the schools in this area and have them stigmatize the low income students by presenting the app as being just “for the poor kids”