I have been thinking to get DD to take the ACT in September of her senior year, but what if she needs to take another one, how late can she take. It is for regular admission
The Sep test is fine for even early action and early decision programs, the Oct test is also good for most early action and early decison programs although there are some for which it is too late for those, the Dec ACT test is the last one the vast majority of colleges take for regular admission, and the Feb test is actually accepted by some colleges.