Original Commentary

Ah, Sydney. I think a photograph of him was shown once in a flashback. He didn't even have an official gender until a year ago; he was just listed as "sibling". And yes, this gives you an idea of Sofia - in Unlike Minerva, she was officially a student visiting the Minerva Theatre for independent study. She wasn't studying anything most of the time. I meant to emphasize this more, but Brisbane had some doubts as to whether or not she was kicked out of school or, at very least, encouraged to study outside so that they didn't have to deal with her on a daily basis - Terrence

Modern Commentary
Back in Unlike Minerva, Sofia's thing was that she wanted to be a princess. It's good for your characters to have goals.

Now, the comic was set in a vaudeville theater. Nobody there had any connection to any monarchy. There was literally no way she could advance her life goal in the context of the comic. There was no reason for anyone in the comic to react to her trying to marry a prince.

You can have a character with unrealistic goals. Look at the manga section of your local bookstore and you'll find a dozen spiky-haired kids who achieve the impossible. The problem is when you have a character with irrelevant goals.

In-universe, I'm going to say it was a phase she went through and is kinda embarrassed about now. Everyone else is too polite to bring it up. - Terrence