How should I come out to my friend

so I would like to thank Rocky Gonzolez for his comment it helped me a lot. it made me seriously consider telling my best friend that I'm gay. so yesterday I had this strong feeling that I should tell her, and while I was feeling this my parents said they were going for a walk and would be gone for about an hour. shortly after they left my brother left to hang out with his friends leaving me all alone, it was the perfect time to call my friend and tell her that I'm gay. so I laid on my bed for a while with my heart pounding and a pit growing in my stomach as I seriously considered telling her. You should know that my friend is mormon too, and is kind of conservative, she supported McCain. she's has gay friends but they are not mormon. I think she will be fine with me being gay but since I am in the church it might be different. I don't know. also I wonder what is the best way to tell her, I was thinking that I could go for a walk find a secluded place in the park and call her and tell her, or should I tell her in person, we could go downtown to the botanical gardens and I could find a place there to tell her. also should I let her know a day or two before I tell her that there is something I need to tell her, or should I tell her without any hint.
After about a year of being friends we were on the subway and out of the blue she asked me if I had any secrets. I immediately thought that she must think that I might be gay. but I kept my cool and told her I didn't have any secrets. She has never asked me if I have a secret since then, and the only thing that she has said since then that could be interpreted as her thinking that I might be gay was about 4 months ago, I was talking to her on the phone and telling her about this really awesome hair product I had just bought. She laughed and said that it was funny that I was metro-sexual (men with a strong concern for their appearance). so I would appreciate any advice on how to come out to my friend. and if there are any questions anyone has for me I would love to answer them