I’m not too familiar with Janis. Always known her name, but not her music.
The earliest popular female vocalist I know pretty well is Marion Harris, who seemed to come along on the heels of Janis. Harris was a big influence on Ruth Etting, whom I also like.
I’m told that as a toddler I knew Ella Fitzgerald’s name, though mispronouncing it. In the 1970s I was able to see her in concert with the Count Basie Orchestra.
Thanks for the tip about Marion Harris. If you can do videos...I found a neat movie clip of her singing in 1928. . .