Souls of Steel by Eva Brandt

No woman has ever piloted a chimera, the legendary mechas that once served to defend Earth from the alien invasion that nearly destroyed us all. No one… until me.
Once, I was a normal girl. Much to my mother’s dismay, I didn’t have any magic, but that was all right. Not every girl carried Gaia’s Gift. There were other things I could do to prove myself, even if I couldn’t heal the earth. I could simply live a normal life—something which should always be treasured.
Maybe I’d have done exactly that had I not stumbled into the mysterious Sphinx, one the most dangerous metallic guardians in the world, considered impossible to pilot even by the most skilled Tamers.
As it turns out, that wasn’t exactly true. I have a natural talent for being a Tamer, a pilot for the elite unit of Chimera Warriors, and I’m the only one who can pilot the Sphinx.
There’s just one problem. To do that, I have to go to the legendary Chimera Academy. The all-boy academy, where everyone will hate me on principle. And I have to face the pilots of my future unit—all born and bred for this task.
Best friends August and Pollux, the pilots of the entwined chimeras Scylla and Charybdis, the heroes who once single-handedly repelled an attack from our worst enemies.
The mysterious, yet notorious Knox, pilot of the Cerberus, a fire-breathing demonic chimera almost as dangerous as its owner.
And last, but not least, Brendan, the heir of the Royal House of Chimera and pilot of the monstrous Typhon.
How can I compare to them? And how can I discover all the secrets Chimera Academy is hiding?