Ah, after some coffee it all looks a lot simpler 😊
Select both Eyes and Apply the Rotation.
I don’t know where that Rotation came from in the first place, but it shouldn’t be there. You have compensated for that Rotation inside your Eye Materials, so you’ll have to undo that compensation:
In both your Sclera and Iris Materials, you should zero out the X-Location (it’s at – 0.05 at the moment) in the Mapping Node before the Gradient Texture:

That should fix it.
If not, just ask again!
Have fun with the rest of the course (as I’m sure you will).
(Oh and don’t forget to get rid of that extra Mapping Node I proposed in the temporary fix in above post.)