関連ワード:  how hard is it to learn keyboard    how hard is it to learn keyboard piano    how hard is it to learn keyboard and mouse    how hard is it to learn keyboard reddit    how hard is it to learn keyboard as an adult    how hard is it to learn electric keyboard    how hard is it to learn piano    how hard is it to learn piano as an adult    how hard is it to learn piano in your 20s    how hard is it to learn piano man on harmonica