They are bluffing. Think about it: If they say you were a bowl of trouble, that’s admitting that school xyz houses trouble girls So, even if you were Lizzie Borden, they would cover for you.
Besides, any parent worth becoming your in-laws knows to take whatever the school says with a huge tablespoon of salt. If you made it thru the term without getting bounced, you were as good as the next 50 girls.
What matters (to some degree) is what your neighbors and family friends will say. What really matters is how you present yourself in the arena. If you go to work / shul / simchas / the park looking like a bas yisroel, thats the label you earn.