Why not? The girls are capable, and despite the whole Fluffyness, this is still basically an elite military academy, with the students trained to be combatants.....
'T ain't Kansas.....
Elite military academy... For kids?
If I'm not wrong MC is 15 years old.
This is also MCs and possibly many of the others first school, and the first year of their first school, no matter how "elite" it is, they haven't even had time to learn anything.
Even ignoring how good they are at combat, do they have any training in detecting hidden dangers or anything?
Before that, they haven't been there long enough for the faculty to place that level of trust in them.
The guards would need guards.
MC doesn't even have any parents vouching for her, she literally just showed up and took a basic test to join the school.
She doesn't even have a valid citizenship... Of ANY nation. Not even a tiny outskirts village to name as place of origin.
If she told anyone her actual family, well who knows what would happen.