I really don't want to have the risks because my health teacher said that there's really bad symptoms. My parents are being unfair! what should I do?

your health teacher needs to but out, your parent are looking out for your best interest

I'd say if you weren't sexually active tell her to wait. If you are sexually active I'd get it. The benefits outweigh the side effects. If you are really adamant about it show them some research about the negative side effects:
"Young girls are experiencing severe headaches, dizziness, temporary loss of vision and some girls have lost consciousness during what appear to be seizures"
I think it will be mandatory in every state soon enough though..

The cervical cancer vaccine has proved to be remarkably safe. The most common complaint is soreness at the injection site, the upper arm. Low-grade fever or flu-like symptoms also are common. But the effects are usually mild. No one in the clinical trials discontinued the vaccination series because of side effects.

WHAT? DO U WANT TO DIE OF CANCER??? there are less serious and total symptoms than there are benefits
get it!!!