I think I would've picked Jane. Since I'm in the US, and Jane was not as popular here as there, I sort of stereotype it as British. Also Ellie, Kate. Depending when the story is set, I guess. Betty seems older to me, like from 100 years ago.- mirfak
Kate is ubiquitous in the U.S. If you watch any American movie or TV show from about 2000-2015, commonly there will be a female protagonist named Kate.