Is it just me? Ambiguous chronology and anachronisms

This is, of course, a highly fictionalized account of Eva Tanguay's career. That being said, I still couldn't help noting how that the musical numbers early on in the picture sounded like "big band" era swing music from a later era; costumes worn by dancers looked like something people would wear two or three decades after the supposed periods in Miss Tanguay's life being depicted; and by the end of the movie it's 1917, when stage show music sounded completely different from how it's portrayed in the film.

Eva Tanguay was born in 1878 and was already in the vaudeville circuit long before the era depicted in her story begins in the film. With era-identifying props mostly and noticeably absent (e.g., automobiles and clothing fashions) it seems as though this movie was purposely making time and dates cloudy and vague; budgetary concerns and the fact that Mitzi Gaynor was only 22 years old (Tanguay was 39 in 1917) are the only reasons I can think of for all the chronological ambiguity.

Okay folks, show's over, nothing to see here!