Very cool idea for a music learning game! Though I wish there was a bit more to it (like notes using further up/down, bringing in sharps/flats, or needing to press the button on a rhythm). It would also be nice if, when you press the correct note, you hear the actual note played, rather than just the same audio clip for every note.
Also, not sure why, but even after a few rounds, I never saw a B note appear.
Overall, there’s a good foundation for a fun music-learning game; it just needs some further polish and more content. Well done!