enrollment for fall 2025

is it too late to enroll for classes for fall? i read on the site the last day to enroll is aug 5th. i was dealing with personal issues & i had to switch my major. so i’m super late. i also wanted to know if i enroll now or later will i rlly have to pay the next day for all my classes? i’m a little confused, if someone could clear things up that would be great. thanks in advance!