Why should you be scared to tell them?
They should be terrified that you're about to tell them they chose to ignore something as important as ASD for your entire life and neglected to do anything to help you with it.
My parents didn't really believe me that it was worth my time and money to pursue testing. It was the last $2k I had and I was unemployed at the time. By the time the testing process was over they were swayed, willing to reimburse me and had a new perspective on all of the traits they had recognized but never thought of as related.
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The Party told you to reject the evidence of your eyes and ears. It was their final, most essential command.
You can't advance to the next level without stomping on a few Koopas.