Lied to insurance company about grades?

I made a fake report card so that my dad wouldn't be pissed off. He sent that report card to our insurance for the good student discount. Is there any way to get out of this? If I tell the insurance company, it may charge me with fraud. If I don't say anything, it may contact my university. I think I would actually be eligible for the good student discount anyway, but fraud is fraud. What should I do?