The question I answered here, in case they change it (which they have done before), was, "If you could travel back in time, what would you tell your 10-year-old self?"
First I would try to persuade her that, no matter what her mother and classmates tell her, she is skinny, muscled and fit, not fat at all, merely a larger clothes size than her shorter classmates. Also, that being the tallest girl in the school whilst in a younger year is not a bad thing. You get to see more of what is happening all around.
I would tell her to enjoy being fit and sporty while she can. That we never know when we may no longer be able to do so and that having to stop sport is not the end of the world (and will not mean that she is on a life support machine - the only possible cause that I could conceive at that age that I would have to give up trampolining, swimming, cycling and roller-skating). That life goes on and, something I am only now realising, there is always something we can do and enjoy. Always some hobby or career and that life does not stay the same or stagnate.
Gosh, this one has really given me a lot to think about.