Very well... you are a courageous young person.
Make it known to them, that you love them no matter what they believe. And that you respect their religious feelings and that you like yours to be respected too.
To do that in general it is better that you don't try to convince from your position.
Sometimes discussions come... but then tell them "I feel that way....."
Their believe in Jehovah is obviously their purpose of life. They don't understand (at the moment) that life can even more be meaningful, when you believe differently.
All the best and good luck.
I am df'd and my parents still treat me the same as before.