I'll see if I can get someone familiar with international filing to assist you.   You said you have been in the USA for 3 years on an F-1 visa.   When did you originally come?  Are you married?

@pk Are you please able to assist here?     Thanks!

@Jeju_Gal , please can you tell me the following  , similar to the questions asked by @mesquitebean :

when did you enter the country with F-1; which country are you from;  how did you earn  enough to have to file a return for the earlier years; do you have an ITIN or SSN ( which one? ); if SSN  how did you qualify for it; how did you end up getting the AOC since it should have asked for SSN; are you here by yourself or are you married  and if so to whom ( US citizen/US Resident/ US national / Resident Alien for tax purposes or a Non-Resident Alien); etc. etc.

Generally the fact that you filed wrong type of return is  fixed by amending those returns   -- filing  1040-NR -- this may also mean paying back some refunds  ( paying additional taxes + interest ); the AOC ineligibility would mean you have return all that monies as part of the amended return.

Please answer  the questions raised , as this may lead to a more specific answer  and the steps you need to follow  to bring yourself in compliance.  It is always better to correct errors before the IRS  finds them ( sometimes they may not ).