Hi there, @SarahTolvtvar ...

Just to make sure ... within your course "Settings" page, do you have your time zone set correctly along with the start and end dates/times you want the course to be available to your students?  Also, when you go to your own "Account" >> "Settings" page, is your time zone set correctly?

• How do I set a time zone for a course?
• How do I change the start and end dates for a course?
• How do I restrict student access to a course before or after the course dates?
• How do I set a time zone in my user account as an instructor?

From a student perspective, your students will have to adjust their own time zone setting via "Account" >> "Settings" ... in the event that you have a student living in a different time zone than you.  This should help students know when the quiz would be available for them in their own time zone.

• How do I set a time zone in my user account as a student?

Hope this helps a bit. Keep us posted here in the Community...thanks!