I don't know if that's all that much better. As soon as you get the notification you're not going to be able to think of much else until you check.

Sure, but I see it as similar to the teacher giving you your test back: you get time to talk to your friends, prepare yourself, whatever before you actually see your grade (rather than it just popping up on your screen). In both, you do eventually have to see your grade, and you're not going to be thinking of much else while the teacher is going around passing out the test. Of course, I hadn't considered viewpoint when designing the feature, so it's not perfect, but I think it does a somewhat decent job (also, notifications are off by default, again, not because I had this issue in mind, but because I didn't want the iOS notification permission alert being the first thing that showed up when users launched the app).

One is during a specific time at school, one is not. That's a huge difference.

But that's no different to the status quo, you know that a grade is coming right from when you sit the test; and IME a teacher will say roughly when the marking will be done, so there's always anticipation.

It sounds to me like this is the sort of thing that needs to be fixed by each person (for themselves) at some level.

Sure, the provider can give multiple options (message with|without grade, message once a week, no message, etc.) but it's still up to the person to choose.

If you're fretting over a grade coming you're going to fret, you need to fix your own notification system.

You could get messages sent to a parent/carer instead, block the number and check them once a week, wait for the teacher to tell you, etc..

Just because food is put on your plate doesn't mean you have to eat it.