I think I'm bi and in love with my best friend?

What I would do is maybe just tell her your bi. Telling friends is easy. Give it time. Maybe she feels the same maybe she doesnt. But take it one step at a time. If telling her you have feelings for her might complicate things, might push you guys aways a little, I would put that aside for now. Tell her your bi and see how things go, if after times you have more feelings towards her than tell her.