Age requirement for Early Decision?

So I just noticed that on CMU’s website (here: https://admission.enrollment.cmu.edu/pages/early-decision-plan), it’s stated that applicants must be at least 17 years of age. Does this mean I must be 17 at the time of application or the time of graduating high school?

I would call to ask. I wondered the same thing when I saw that. I know they are very strict about students turning 16 prior to staying in their dorms even for high school summer programs. Neither of my children was old enough to attend their summer programs while in high school.