daughters 21st party

My daughter turns 21 next year, I want to give her the biggest/best party ever! I have decided to have it on a boat on the thames (hopefully by south bank ) her favourite place. She has been through hell the past few years, living with stress, a from of eating disorder, anxiety and quite recently shes not been in a very good place. She always thinks of other people, she always wants to help and join in and never thinks of herself. I think something should be done for her. She doesnt realize how many people care/ love being around her.This will hopefully give her the biggest surprise ever and put a smile on her face, however she does not know any of this is going on so keep it under wraps.