Why turn it into an app though? This kind of learning materials is something that can be done in a construction of a website which is more accessible for everyone as an app would just simply make them download and as well clear/allocate some memory for your app.
Mobile applications are intended for convenience and ease of access. The OP seemed to develop this due to academic purposes. We know that it is really hard to trust installable applications, yet if it was accepted in both Google Play Store and Apple Store, there's not doubt that this is safe. The app also requires the following permissions:
Photos/Media/Files- read the contents of your USB storage
- modify or delete the contents of your USB storage
Storage- read the contents of your USB storage
- modify or delete the contents of your USB storage
Other- receive data from Internet
- view network connections
- run at startup
- full network access
- prevent device from sleeping
Those permissions are common in many informative applications and doesn't really have any harm on someone's device. This would be better if the OP would publish his code in github for a better in-depth analysis of the system. Yes, interactive websites are better but there are certain situations, especially when it is for academic purposes, that building it in a mobile application is wayy simpler than publishing and hosting it in a website. Also, note that there are tons of websites that also offers the same thing.
Therefore, application like this is still better and would be best if published to be an open-sourced app. @OP, if you worry about gaining profit out of you project, such informative application shouldn't be your choice as you cannot have any clients to cover your costs. Better publish a donatable address in your app and website as well.