My gay sister was same way before she told our parents. Of course they were disappoint at first, now our mother want to see my gay sister to be happy with her partner than live alone rest of her life.
My parents went to see their priest and asked his help on this one, this priest helped my parents by accept my sister for who she is.
Your parents will be disappoint and sad but time goes things will become better. I hope for your sake. U desrve to be happy.