Whether you think you need financial aid or not, the UCs recommend you apply for FAFSA, which is the Free Application for Federal Student Aid.
One reason you should consider applying even if you feel you are straddling the fence in terms of eligibility, is a FAFSA application can possibly open you up to scholarships you might otherwise not be eligible for. (Some scholarships insist you have filed a FAFSA.)
The FAFSA application window opened on January 1. The sooner you apply the better your chances because it’s based on a first-come first-served basis. Once they run out of funds, even if you’re eligible you maybe be left out in the cold.
To do a quick determination of eligibility, go to the FAFSA eligibility page.