Can you mark a different race on a census form than you marked in previous years?

I don't view myself as white, but thanks to my mom, every form I am listed on has me listed as white. Being that my grandmother's side of the family has black admixture and my dad is so dark he looks like he's from India, I don't think it'd be an accurate depiction of my ethnicity if I am checking off the same box on a form as an Irishman or a Swede.