Nova and the rest found Mira's tenacity and adaptability respectable. She didn't back down when things got tough and constantly looked to overcome the wall that was before her.
While Nova's Sunfire Sphere Spear techniques weren't the most powerful in her repertoire, they weren't something an average person could handle. If she were to fight against anyone in the same Realm as her that wasn't part of the Top Sects, she'd be able to defeat them 80% of the time with just her Sunfire Sphere Spear Shots.
So, the fact that Mira was still fighting proved she wasn't ordinary and that, if nothing else, she has a strong mind and body, which is what the Battle Maiden Sect looks for, beyond just talent.
