Reminder Times for Studying for the SAT

When Studying for the SAT, Khan Academy allows me to ask it to give reminders for me every day until the test. This is a good feature, but I have set it to remind me at 6 AM because it can't remind me earlier, for some reason. I'm a morning bird and I would like to to remind me at 4 AM, but it doesn't have that capability, and I don't see why it would be so hard to allow that. 

Thanks!