Svenja is not part of a school despite her age. She lives outside of the city and depending what time of Day it is, she could be arriving at the gates for entrance, at work, or wandering around the city on her day off.

 Maybe she over hears a conversation that draws her to other characters. Maybe she sees something suspicious or curious and seeks out what it is. Or maybe something dramatic occurs where she can jump in to help sort it out. Those are some options I brainstormed. But whatever you guys come up with, I can morph around.