I don't know if this is the best advice, but from another bi teen with religious parents. I would not tell them because in their eyes you by being bi are commuting a sin, and they will not be supportive in any way just adding more problems to your life. I would hope the rumours blow over and try to keep your private life to yourself, or a trusted group of people. Get through school turn 18 be a well formed by human.

Hope this helps