Just be yourself, approach it like you want something to happen.
She's ginger? I know several girls that are ginger and they are stunning, hair colour doesn't matter at all. You like her? Yes, that's all that matters. Get to know more about her, then when YOU feel the time is right make the infamous move

but don't rush.. trust me, I know.. rushing things isn't the best.
Oh and most of all, be confident about it.. you said that she's really really fit, like you have no chance with her? That's false, everyone has a chance with everyone.. it's pot luck you win some and you lose some.
Just good luck with it and I hope it all goes well for you