Not necessarily. 'Musica' could be a blend of real-life inspiration and imaginative elements. It's hard to say for sure without specific details about the particular work in question.
Quentin Tarantino is the one responsible for the'musica' in 'Pulp Fiction'. He's known for his amazing use of music in his movies. He carefully chose a wide range of music from different genres and decades. This blend of music gives the movie its distinct and unforgettable flavor. His choices were not random; they were made to fit the mood of each scene, whether it was tense, comical or just plain cool.
Nezuko is initially 12 years old in the manga. As the story unfolds, her age doesn't change significantly in a traditional sense, but her character development is quite remarkable.