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

[InvisibleFilling]

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).

[SundayInSalem · Accepted solution]

You filed correctly. Great job!

F1 visa holders are generally exempt for any part of five calendar years, meaning you will not file as a resident alien until your sixth year in the United States. Assuming you spent more than 183 days in the U.S. in 2020 (satisfying the substantial presence test), then your residency began on January 1, 2020. 

See Example 1 in Alien Residency Examples.