Sophie, who is from Llandeilo, South Wales, also raises money for a children's charity.
The teenager is now looking forward to a normal family life and continuing to be an ambassador with Rays of Sunshine.
Sophie said: "Finally getting the call to say we've found you a donor organ, the RAF are on their way to collect you" was so exciting. And since my transplant I feel really, really well. Please sign up now and tell your loved ones about your wishes. Life is the most precious gift of all. Pass it on!"