Should lines get darker even in early early tests?

Bo

I’m testing way too early, I know that. 6dpo, 7dpo, and 8dpo, I’ve seen squinters on each. You guys have seen the lines. But it’s not really getting much darker. Is that because it’s so early and it’s barely registering, or what? For reference, here’s 8 dpo (not fmu), I see faint pink in person.