XAMK

[wow]

I've a couple of courses set to begin in May. Enrolled in one, but when I try to use the enrollment key for the other it says "incorrect enrollment key". 

I'm wondering if the course that popped up in my search is just an old one and the new one isn't up yet. Does that sound right, for a course that begins in a week to not be available for enrollment yet?

That sounds right to me. I have only ever been able to enroll in a course once it starts, or maybe a day before if I remember correctly. I have never been able to enroll in advance.