Josei means that the content is geared to a more mature or adult female audience, so this absolutely could be a fitting tag. However, it also should have a yuri tag at the very least, as it's concerning a storyline that depicts romance between two women.
That said, here's hoping the author does something more interesting than the stereotypical "I loved her but she broke up with me For Reasons to go marry a dude instead" trope. And that our mousey little MC ends up kicking her horrible long lost love to the curb, and maybe runs away with her Twitter-friend...