"You're a racist and I'll prove it." Right, so start fighting the wealthy elite who keep poor people of all skin colors poor. If we're both drowning but I'm 5 feet closer to the surface than you are, I can't help you as much as the guy on the surface with the dive boat. Step 2: accept that the moral burden of achieving equality lies on the oppressor, not the oppressed. However that's defined. Men, straight people, cis people, white people, the rich, whatever. Step 3: do something about it. Lovely words. Nothing actionable. If you mean 'Do you oppose people who make judgements based on melanin content of skin?' then I am an anti-racist. If you mean 'Do you unilaterally support BLM on every single issue?' Then I am a virulent racist, because I think skin color is the least interesting thing about a person. That's false, and I have a feeling your reluctance to take the IAT has something to do with that.
b. Treating people equally when they start from an unequal position reproduces inequality.
Step 1: acknowledge that your own identity is tied up in pervasive notions of whiteness. Do your best to limit their influence on your actions, but recognize that you probably can't change them.
The question is, are you anti-racist?