It is totally up to you if you want to get the AP credits or not. At my D’s school, she may withdraw any AP credits by the end of the first semester. However, she would not get the advanced placement by doing so as the equivalent class/credit would be removed from the transcript. In any case, it would not be a problem if you want to retake a class to forfeit the AP credit. Calc3 is a kind of tough even you do very well in AP Calc BC.