How do I and/or should I come out this dark a$$ closet?

Guys Im a 18yr old female who recently found a chic who is cool and wants to sleep with! lol i need to kno whether or not i should tell my family bcuz i think this is gonna b a permenant thing b/w me and her! Everybody in my family thinks im straight. My immediate family are like crazily devout christians and i kno they will freak out! they may even put me outta tha house! should i let them know wats goin on and if u think so how should i do it?