If I am on an F1 visa (including OPT) from 2015 to the present (May 19, 2021), am I consider as NRA or RA?

I had already filed as RA for tax 2020 because I was not sure how the "exempt individual rules" work and I followed blindly with international friends around me. I had talked with the TurboTax specialist but it seems that he/she not sure too (as it could be the way I'm asking or listening incorrectly).