Course Challenge Start Over Button

The course challenge is a really hard test; not being able to go back if you're unsure about answers, erase and double-check stuff, makes it VERY HARD, especially when you include misclicks. All of which makes the test almost impossible to get 100% on the first try, and for some reason, you can't restart it

Is it important to get 100%?  I would have thought 90% or 95% would be good enough.  (For context, I often got 100% on school projects and tests, but I have learned that perfection is rarely possible nor necessary.)

It isn't necessary, but it's annoying that if I want it to just look "shiny" I gotta take the test multiple times and try to complete it to my best ability every single time I get even 1 question wrong

Do you have to get 100% specificly on the course challenge? Thats tough. I can't do that.
I always end up with a few wrong.