The Beast Trials: Meadow's Beginning by G. T. Jones
Meadow Woodley hated being a teenager. Self-conscious, and with few real friends, she spent most of her time at home, begrudgingly looking after the neighbour's hideous cat. That is, until a few days after her sixteenth birthday... Discovering that your dad is actually a beast, and comes from an enchanted world called Elementa, is a lot to process. But finding out that you are also half beast; have to travel to this strange magical world, and must compete in a series of terrifying, potentially life-threatening challenges in the company of almost fifty other teenagers is surely taking things a step too far. Still, it couldn't be worse than her current life... right?