Seriosuly bro, If you've got the game take both of em.
Message them both say something along the lines of "Alrite, since you both want me how about we go to the prom together... that is if you can handle this."
If you can't deliver what you're offering then dont do it though. Alternatively just be real with grl one and let her know you just want to be firends if she asks you. Go with girl 2, it probably wont mess up their friendship... and if it does you can end it after you get what you want. Or if you really like her you can stay with her... it's all situational.
Message them both say something along the lines of "Alrite, since you both want me how about we go to the prom together... that is if you can handle this."
If you can't deliver what you're offering then dont do it though. Alternatively just be real with grl one and let her know you just want to be firends if she asks you. Go with girl 2, it probably wont mess up their friendship... and if it does you can end it after you get what you want. Or if you really like her you can stay with her... it's all situational.