What @DefyingDepravity said
I've worked in similar student part time roles and made myself stick it out for a reasonable period
I don't regret anything, life is life, reality is I was playing a martyr...some environments can be toxic if your face doesn't fit.
A lot of people will target someone based on their appearance and demographic..
All the assertive comments and good social skills don't mean anything if someone has honed in on someone because they're a young female, or wrong face for the environment.
As I said, I stuck it out.
The reality is I had the skillset to do other forms of (paid) work and I should have leaned into developing these rather than flagellate myself for minimum wage.
It's not necessarily character building, just taking away time and energy from her grades or building up long term skills.
Some people are extroverted/thick skinned/feel they can get great tips from customer service/enjoy the hurly burly.
If not, it's often just a waste of time for a small amount of money.
Or if it's just part-time work around studies, keep an eye out for roles where her face fits.
For example, there's some small posh offices which want "nice", well presented, softer people as their front person. A polite sixteen year old would be great.
I used to do one day a week paid as a charity receptionist, one of the full time workers wanted a 4 day week so I was perfect for the role.
Or often third sector organisations want volunteers, and if they're good they get moved onto paid work. Maybe a museum or something?
It will also help with building better social networks and references than a customer service role.
I didn't need it at the time, but some of the posh alpha people at the charity offered to take me out to meet their groups...if I'd wanted to engage with these there would have been a great opportunity.
Many people get jobs or partners through this kind of jig.