Simula

Jeanne Asuncion was six years old when she met her ultimate crush Phoebus Acosta, she was half his age but it didn't stop her. She even wrote him a letter confessing her feelings for him, but Pheobus rejected her and even called her a 'kid'.

Well, that's in fact true that she was still a kid, but Je's immature mind back then can't process it, so she believed that it was her very first heartbreak and swore that she would never have a crush on anyone ever again.
Eleven years later, they've crossed paths in a most unexpected way-

-Pheobus Acosta was now her Professor in her most hated subject, Finance.