That's exactly what you should do. Go in to the admin office and ask what it takes to keep your records private.
What difference does it make? If the school person says no what are you going to do, hire a lawyer for $300 per hour, stew over it, come back and ask what are my rights?
One of the things that you need to develop when you become an adult is priorities. This is not one of them. You'll have a lot more and bigger problems trying to survive out there as an 18 year old with only a high school education.
Put your parents and this issue in your rear view mirror and let them disappear into the distance.

