Balloons and streamers? Carvel cake? Those might be standard fair for your average birthday party, but Whitney Blake and Sophie Mitchum are anything but average. I'm Laura Finnegan — thrift store junkie and scholarship student at Tate, our posh all — girls high school in Manhattan. I'm not like Whit or Soph, but that doesn't stop us from being BFFs. But then they started tuning in to the all — Sweet Sixteen, all — the — time channel. Now tempers are flaring, Prada bags are flying, and guys are being tossed around in vicious tug — of — war battles. Whose Sweet Sixteen will reign supreme?