If you were not and are not a dependent, you would answer no when it asks you if you were a dependent.

But the main question was if I ever received the American Opportunity credit previously, before 2018, and I did receive it but it says to click "yes if one was a dependent", but if I click no, wouldn't I be saying that I havent received the credits even though I have on my 2017 tax return?

If you have received the credit previously and the question is asking if you have received the credit before whether as a dependent or nondependent click yes.

  The AOTC is only allowed for 4 years PER STUDENT.  This means if you or someone that claimed you took the credit a combined total of 4 years you will no longer be eligible for it.