How much time did you spend with students validating the concept and materials before putting the app together? It's important to know who your target audience is before choosing the appropriate method to reach them.

Regarding the specific ASO side, don't worry too much about the app description beyond the first couple of lines for getting the core USP across. Definitely work hard on your keywords and screenshots though, and keep a close eye on your App Analytics account to see how many visitors you are getting to your page and the conversion rate to installs.