Young champion diver Xanthe only has free-time for Julia, her bestie since primary school, but can their princess-promises survive their dreams, different schools, new friends and injury? Can two princess-wannabes stay friends as they follow their dreams? Of course they can!

Hi,
Sorry but this doesn't sound like a log line at all. Quite long, uses questions, doesn't articulate the goal of the heroine (It is Xanthe right?) What is the intent behind using the term princess-wannabes? What dreams could be 'lost'?

At present it reads that Xanthe spends all her free time with Julia, her best friend. Even though they go to different schools and have other friends.
Who gets injured? What is the injury, is it enough to stop them being best friends? Do I care?
Try a rewrite that will make me care, but only use 25 to 30 words.