Domestic Partnership (CA): Can my girlfriend and I register, we're both 25 years of age.

Yes, only opposite sex couples of that age can register as domestic partners. The law is unfair, because opposite xex couples your age have to get married, and same sex couples your age have to register as domestic partners.

In my opinion the state should get completely out fo the marriage business, and should only "espose" everyone, regardless of sexual orientation.

Please see the FAQs linked below.

Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.