Lovemydd has some good ideas. But I would hold back from deciding at this point that K will not work for your child (unless you already know you want to homeschool). Many children do come into K already knowing much of the basic K curriculum as it is described online. This does not necessarily mean that K will be a disaster, although it could be. There are a lot of other factors involved--your child's personality, the school's curriculum, the teacher she gets, the school's flexibility. I have two children, one of whom attended K at a small charter known for very high test scores and one of whom is in K at a poor Title 1 school with low test scores. My younger child is probably the more gifted. While neither came across any reading or math they did not know in K, the older really needed to learn how to "be in school," and also enjoyed school, though generally it was a poor fit but not awful. My younger is now splitting his time between K and 1, and really enjoys the social aspects, things like art and music, and has grown tremendously in writing skills (something most kids don't really pick up at home). The Title 1 school has been far more accommodating of giftedness than the charter. Despite the fact that actual learning was/is limited for both, I would not have chosen to HS them and feel that K has offered benefits. Of course, HSing is also not something I want to do unless I have to.
