The Guy She Was Interested In Wasn't a Guy at All Vol 3

From the Yen Press edition

After hearing Mitsuki’s song, an excited Aya encourages her to share it with the world! Mitsuki is more than a little hesitant to put herself out there, but with Aya’s support and inspiration from a music festival they attend together, she begins to pursue her passion in earnest. When a certain video of her singing goes viral, though, Mitsuki ends up becoming somewhat of a celebrity at school…and her newfound fame brings difficulties for both her and Aya. What trials await the pair in their final year of high school?

Source: Yen Press