how did you know you were really reading?
When your teacher told you "good job" and you tested well for your comprehension.
When did you know how to tie shoe laces
When your parents told you "Good Job" because you did it the way they showed you.
When you have a job, how to you know when you know your job?
When you followed instructions and your boss or piers told you "good job" and your boss gave you a positive review.