Looks like it was a small part, I suppose typical given that it was her first film - MGM had some faith in her, but not enough to make her a star right away - in fact that first film was a loan-out to UA. Did you get to see a lot of films when you were a kid? My mom, who grew up in a rural area and whose family was pretty poor, told me she never saw a movie until she was 14 or 15 - Green Grass of Wyoming in 1948.
Pretty sure I've confused Jane with Eleanor Powell more than once - both co-starred with Astaire, both had relatively small film careers, but both fairly big names to the classic musical lovers. I guess I'm still not a hardcore enough fan of the stuff to keep them straight all the time or to be able to call to mind what makes either of them distinctive, but I think some of that has to do with neither of them really being in many truly significant films. Still it shows just how much song and dance there is for me to still explore.