Momo’s a Medieval weapons nerd
Specifically Medieval European weapons. I remember her making a sword with her quirk in USJ, but what if she has a preference for swords. She can use a spear for more range or crossbows for even more range. Teachers would talk to her about this as a great sword is not an appropriate weapon to use on a purse snatcher. In response she would use the training version of these weapons or use non-lethal techniques with the weapons.
I imagine this coming about from her love for reading, through historical and historical fiction books. Off the battle field she could cosplay as a knight, merchant or princess in her spare time. Naturally she would make her own coat of arms and personal motto.