Fabulous 13th? please help?

Me and my friend are planning her 13th birthday party and we really need some ideas and some voting. Well we really don't know where to start, she wants this to be her best birthday party because it's her last one until she's 16, so what should her theme be? Candyland? 12 going on 30? Pink wonderland? Super Star? Americas Next Top Model? Please help!!!!Also what should we do at the party, how much should we invite how much should we spend on it? OMG THANKS!!!!!

Sorry if this is the wrong section, but I really need help

how about a princess theme ?invite everyone that you know even some princes.