I don't know about the LN, but in the WN it wasn't Mimi's classmate (or, she didn't describe it as such), it was Mimi. She was the one with a boyfriend whom she lost to a maidroid.
While both versions of the story fit Mimi's fears well, it is interesting to imagine how her story would have changed had her former boyfriend not dumped her.
Like, she would have had the support and counsel to both reject her parents' debt and have a place to live until... I'll stop there as there's massive spoilers, but she would still most likely end up a space mercenary, just without Hiro, so she'd also probably be more cynical and not be part of a harem.