Welcome to Wrong Planet!
Not to be a downer but from my experience it is just easier to stay in the closet.
Unfortunately, many people will just never understand, and you will have you accept that. You can spew out facts and figures about Autism as well as personal lived experiences that aline with the diagnostic criteria, until you are blue in the face, and people will still believe whatever they want.
I'm not saying give up on your parents or family just yet, but keep your expectations low for the time being, it may take some time for them to come around.
Fortunately there are people out there who will believe you, surround yourself with people who accept you for who you are and are supportive. I would look into attending a Autism support group in your area, if one is available. I have benefited from such groups in the past and really enjoyed them.
Good luck on your Autism journey, and I look forward to possibly reading about it here in the future.
Cheers,
CFL