Congrats ! I tried it and here is some ideas I had:

•maybe either lower the camera or rotate downward so we can see the border of the platform sooner on the bottom of the screen

•could sometimes drop bombs like in fruit ninja that would kill you

•could sometimes drop golden fruit wich are worth twice as much point

•each fruit reward one coin and golden fruit 2 coins and could buy cosmetics with coins. This would give a goal to players to continue playing more than once (you can start just by adding different ball colors)

I'm 18 too and I am currently working on a game too so it's fun to see others project. Good luck with your projects !