How do I tell my family

Hi all, (those who can be bothered to read anyways)

ive very recently been diagnosed as autistic, my parents, who i dont live with and havent for years, seem to not accept the diagnosis 

my parents and wider family dont understand or seem to want to acknowledge that im autistic.

it answers a lot of the questions i have had regarding how i care about people or understand why people seem to care about other peoples problems, to put it bluntly

has anyone had any experience with this  or has any advice to “politely” tell your family that there are some things that just dont bother you, or things about people like there problems that you just dont really care about or understand?

thanks