Is the bride the only one that wears white?

While talking to FH grandma, I asked so what did you decide to wear. She says a white lace top and pants! I'm speechless, say nothing and then when we are done talking, I say to FH, your grandma is wearing white and he says isn't the only one wearing white is supposed to be you. He then calls her and says the same thing and she says yeah, and!! That's what I have already to wear. He then says please go buy something else then. So I have no idea if that is going to happen or Not! I just dont know how im supposed to feel about the whole thing. Did she not even take my feeling into consideration?? I'm a week out!!!