Over 1k active devices and ~50 active users daily.. Next step?

Hello everyone,

So a bit of background from my side:
Approximately 8 months ago, I have released an app called BioPlus, which helps high school students study biology for their final exam (in Romania).
The app contains the necessary knowledge for them to pass, plus over 2000 questions (extracted from the exams from previous years) bundled as quizzes, which the users can take whenever they like.

During these 8 months since the launch of the app, I managed to grow the user base to around 1k active devices and an average of 50 active users daily.

I have to mention that I barely did any marketing myself. The only source of users was either organic from Google Play or from an older similar app (3.4k active devices) that I have.

The question I keep asking myself is what would the next step be.

Why do I keep asking myself this question?

Around the same time I launched the app, I co-founded another start-up, which currently occupies more than half of my spare time
Another reason is the market for this app, which probably sits at around 30k students every year (not a very huge market, but more like a niche)
The lack of an "invest in yourself" mentality of the my target audience, which sort of influences most of my ideas to change the business model I'm currently running (free with a few ads here and there)
The nature of the app, which is "seasonal" (new users coming in every year and old users leaving after the final exam)

Why don't I just dig a grave for this app?
Seeing people wanting more than what it's offered (the poor education the school gives you) drives me to think about ideas and features I could add to make the studying process even friendlier and easier for the students, people that appreciate my work for what it is.

So I thought about coming here and getting some frank opinions from you, people that already have/had start-ups, people that are madly in love with entrepreneurship or simple people.

Thank you for taking the time to read this post, and God speed in all your endeavors.

Andrei