“I’m just not a math person” is a sentence you said, not a fact you discovered.

Somewhere a bad month with fractions hardened into an identity, and the identity is more comfortable than the struggle was. Calling it a fact about yourself ends the argument early, which is exactly the appeal. But a sentence repeated often enough starts doing the work of evidence without ever being tested.

Take the subject you wrote off and give it twenty minutes with a fresh page and nobody watching. Not to prove anything, just to see what happens when you go slowly. Plenty of people find they were never bad at it, only rushed through it.