You shouldn't need a parent's permission to help out. Check out either
http://www.noonprop8.com or
http://www.eqca.org/site/pp.asp?c=kuLRJ9MRKrH&b=4375153 or
http://www.votenoonproposition8.com/
for contact information for various groups dedicated to your cause. You're never too young to become a part of the political process.