Help with telling my best friend Im bi?

Just tell her, when I told my best friend she was totally supportive, she even made a joke that I should date her cousin (she didn't know I liked her cousin at the time). My friend wasn't surprised because I wasn't really going out with a lot of boys and I looked at girls a lot. He also knew by the way I acted. (I use to be a tom boy, a really bad one) lol. It isn't a really big deal :)