Immediately Damon said this, Jennifer's eyes and the instructors' shone with deep surprise. Then they looked at her and began to offer their congratulations with amiable smiles in their faces.
Jennifer nodded and smiled back at them. She was incredibly happy but she didn't show it.
Why Damon made Jennifer the principal was because Jennifer was powerful enough to fight and kill a sage general-stage expert by herself. He believed the others wouldn't be able to accomplish such an impossible feat. So he put her there to fill the empty post as he felt only her was worthy.
Being a principal, more cultivation resources would be delivered to one. The cultivation materials that would be offered to anyone in this post could be said to be one that would support the cultivation of a grand saint emperor stage-cultivator.