It happens. You might have to switch to the All classes view. Only classes that you're the teacher of will show up under the My classes view on your classes page.
1. Click on the downward-facing arrow next to My classes to switch to All classes.
2. It should say All classes instead of My classes.
So if you've just created a class, and you're not the teacher, you can view that class by switching to the All classes view. Simple!