[Alle meine Entchen]When I said that some adults may "have a hard time" to learn stuff like that, I meant the challenge of being confronted with such "childish" music as an adult. That's one of the obstacles adult beginners have to be ready to overcome: At home, they may listen to Beethoven, Chopin, Bartok, Oscar Peterson, Miles Davis, Keith Jarrett... but in their piano lessons they have to learn "Alle meine Entchen", "Merrily we roll along", "Jingle Bells"... This gap between their musical taste/understanding and their own humble efforts may be experienced as frustrating.
How do I "break up" with my teacher?
How do I "break up" with my teacher?.