That Certain Age (1938), directed by Edward Ludwig.
Fairly bland Deanna Durbin (age 17) entertainment product, in the "let's put on a show" genre.
She's smitten with an older man, the acerbic Melvyn Douglas, and throws over boyfriend Jackie Cooper, who always looks like he's about to burst into tears. A few years earlier he was famous for his weepie films.
A moderate amount of singing, all part of the story. The rich country house setting is what people wanted to see during the Depression. We get a glimpse of perennial butler Charles Coleman. The IMDB shows Billy Wilder as an uncredited writer.