She could just be shit-testing you to check your reaction. Take her out for drinks and don't bring her bisexuality up. If she does bring it up, behave like "it's no big deal". Let her know you are cool with it and you can handle competition from guys and girls. Do what you would do with every other girl, keeping in mind that she must be sexually more open since she discussed her sexual preferences. This means escalate, escalate, escalate... If this evolves towards FWB you could even score a 3some... Lucky devil
