The Best Friend Issue

I'm only out to a few people. In high school, I think I was fearless and out to everybody, but now that I've come the the midwest, I'm often very nervous about who I tell. My first year of college I came out to a few friends one night while drinking, and only one of them I really feel like is my friend anymore, and he eventually came out as bi to me a year later. My boyfriend knows that I am bi, which seemed difficult for him initially, but now he's fine. Until very recently, I've been ok with being someone in the closet and someone out. I'm not an activist, it's not a part of my daily life. Even in high school when I was much more open, this was not a huge part of me, because there are other parts of me I think are more important (being a good student, getting into graduate school, eventually being a mother). I kind of miss that, miss feeling comfortable not being out. Now however, I feel like I'm lying, even though nothing has changed.

Biggest of all is my best friend. When I first met her, she had just come to college and she was an army brat, rather conservative, and not someone I would be open with under the best of circumstances. But, in the past few years, she turned in around and become someone who I would want to be out to. Unfortunately, she still doesn't know many LGBT folks so even though she says she's supportive and loving, I still don't feel like I can trust her.

I feel wrong not sharing this with her and calling her my best friend, but I don't know how to tell her. Any thoughts or advice?