UWC 2018-2020, I need advice to get better.

Hello,
I most certainly know it is early to be worrying about this already, but I really am triggered to get in… UWC has been my dream for over three years and, every time I talk about it, some sort of fire grows bigger and stronger in me. I love culture mixing and different opinions: knowing people different than me is THE BEST WAY to learn.
My name is Marina Meredith, I am both Spanish (Barcelona) and British and I go to a French school. I learned about UWC when I was in quatrième (at the end of year eight, I’m now in year eleven), thanks to some of my mom’s friends and work/university colleagues (what is rather funny is that we keep on noticing that we are “surrounded “of ex-students of UWC).
My grades are between sixteen and nineteen out of twenty (knowing that my French system is tremendously harsh while marking students) and my global average -that is how my school calls the average of all the averages of a student- is seventeen and a half out of twenty.
Culture wise, I love everyone and each of them, especially when we are talking about traditions, customs, food, legends, and the language. I speak French, Catalan, Spanish and English and I have been learning Chinese for about six or even seven years and I have only just started learning Esperanto (a language that had been created right after the second world war envisaging to be the language of exchange in the world, to be able to get populations together and prevent from a possible third war)
My hobbies are tennis, kungfu (wu shu, to be specific), drawing, cycling, surfing during the summer, skiing during the winter, my Chinese classes, singing and dancing, interpretation, writing stories, and debating (I am at a club and we compete with other French Lycées from all over the world about climate change and sustainable future: we also create projects). I love any kind of sports: swimming, climbing, running, badminton (should I include hide and seek?). I love any kind of sport that implies competition and use of extreme energy, really.
Social help, here in Barcelona, is extremely difficult to find, especially if someone’s fourteen-fifteen (and, nowadays, associations keep on relating volunteers to ex-university students that are looking for something to do and get a little cash). But I am getting somewhere: I have finally found somewhere to help for two weeks in the summer (so that I can help immigrant’s children, about five years old, to learn Spanish in a fun way and integrate in our complex, Catalan society).I am also a volunteer in a Chinese association for the new-year celebration in Barcelona and I participate in some of my school’s activities (I am also really hoping to be able to go to theatre classes at school).
I have tried this year’s application form, but because I am from December, I have to wait for another year and I only have one chance to try to get in.
I am willing to go to UWC Xperience and to voyage to China with that same Chinese association from before.
Oh! I do hope I get in!
I know I must get better, but I need some advice.
Thank you so much for your help
^:)^