I don't know. Am i a bad boy?

I'm not a good student. I don't know what's that mean. Am i bad boy? I tried all that time to do well, but finally i can't. Recently i complete my HSC exam, everyone think that i'm going to pass. But i know i'm going to fail. My dad know i'm going to get GPA 5(A+). I don't know what to do. I always found myself alone. I'm confused. I don't want to tell them about this .What can i do?