American Diploma Issue with AP requirement

I was admitted for the upcoming school year. I am an american and I saw that I need to send them 3 passing ap scores of 3 or above; however, I only have 1 documented at the moment (AP Calculus AB with a score of 4). I am currently taking AP Calculus BC and plan to take that exam. My only issue is that I am only doing the AP Macroeconomics exam and no class. I am confident I will pass AP Calculus BC, but I am not too sure about AP Macroeconomics. In the event that I do not pass AP Macro, what should I do? Will my offer be rescinded or I am still okay if I tell them my situation? I did not know about this requirement prior to application time and I only learned of this last week.

Any fellow americans who may have had similar issues, I could use some advice. Thanks.