If nothing else, you WILL find out if she's your very best friend in the world. If she is, she'll accept it. Perhaps not right away, but she'll come around.
I have told some friends and not told others. That was not my decision, however. My hubby demanded that I tell no one. But... I just got divorced and now I can't keep my mouth shut. I am not ashamed of who I am any more. I'll likely never have another relationship so why not be somewhat open about myself?
Cindi