Hello gbeam,
Thank you for using Apple Support Communities! I understand that you are seeing unexpected charges for an Apple Music subscription. You've come to the right place for help.
Let's start by determining what type of Apple Music subscription you currently have, and change to an Apple Music Student subscription if needed:
Manage your Apple Music subscription - Apple Support
After that, we'll want to check your purchase history to determine what type of subscription you were charged for. You may also be seeing an authorization hold to confirm your payment account is active:
If your purchase history shows that you were charged for a 3-month Apple Music subscription, the next step would be to contact Apple Support:
Apple - Support - Product Selection
Take care.