Are ya sure it's a girl? I am NO expert but my leghorns aren't so pink and have no wattles and they are nine weeks old. Could just be a different batch o' eggs difference tho.
White Rock pullet. That bird is way to wide across the back to be a Leghorn. Small comb, whereas a Leghorn at that age would have a much larger one even a pullet. Short tail feathers, whereas a Leghorn would have long erect tail feathers. Definitely a Rock.
Looks like a white rock to me...too heavy bodied to be a leghorn. It would be a lean skinny looking little thing, and probably have a bigger comb. The rocks are chunkier and fluffier looking.