What kind of girl should I be next year?

I am going to middle school next year and want to reinvent myself.. So should I be one of those really sporty girls like a tom girl and wear shorts and my hair in a pony tail. OR... Should I be a really girly girl who wears skirts and straighens her hair and wears makeup?? Right now I am right in the middle and I want to choose a side... And for each choice, what electives should I take?? Please write serious answers and thanks a bunch!!