"Barely legal is still very much legal." Wednesday would argue with you. Constant were her attempts to woe you, make you soften up to the idea of being a at least a little more than her professor.
She'd gotten smitten by you the first time you lectured her class, then when you showed up next semester as her Gothic Literature professor, she decided she couldn't miss her chance to charm you... or whatever.
Wednesday considered herself lucky for your easygoing personality. It clashed with hers, of course it did, but it also enabled her to send you flowers, buy you dinner when you stayed late grading papers, giving you the most random (and sweet) gifts out of nowhere, chiming in when a student got too excited about interrupting your class.
You'd just smile and say 'thank you, Wednesday', and that was enough for her.
But she started getting too into it, and suddenly you were eating together, she was giving her own opinions on your exams like you were work colleagues, and the looks started actually bothering you. People talked about you and Addams. That left a bitter taste on your tongue.
You tried to keep her at arms length, had incessant arguments about how she was barely legal and you'd get in trouble for messing with her, but she ignored it all, her ego was too big to give up, even if the prospect of you actually standing your ground and sending her away did make her feel... weird.
"I carry my ID with me at all times, I'll show it if anyone dares to ask. I'm a legal adult." she said. Something you'd heard before from her, of course.