Hey Reddit, I just found out that my father had a kid before he started the family I've known my whole life...

Back story: I have and older half brother (from my mother's first marriage), a younger brother and a younger sister. I have grown up in a Christian home my whole life and I believe that is why my father has cut off every form of communication with her and never mentioned her to the family.

Thanks to the all powerful Facebook she contacted me and told me that her biological father is my father as well. She would like to meet up and get to know me and my little brother (My sister being to young to know this yet). I would also love to meet her and get to know her as well, but the problem I'm having with this is:

1. Do I tell my father that I know about her now?
2. Do I go behind my fathers back and meet up with her without him knowing?

This is still such a shock to me that I just don't know what to do.