You have an agreement problem in the main clause. "Shoes" is plural and "shines" is singular.
Her black shoes ever shine, etc.
I'd call these piggyback appositives. "Never begrimed with dirt" is in apposition to "shoes," and "not even at the time when school ends" is in apposition to "never begrimed with dirt."
You are welcome Sundarnaz. And I don't agree with you. You should post it whenever you need the help. Besides it will aid you and help you write better the next time. Best of luck.