22-year-old Petra Anderson is truly lucky to be alive. Petra was at the midnight showing of "The Dark Knight Rises" in Aurora, Colorado, and was one of the people shot that fateful evening. She was hit four times: three shots in the arm and one in her brain, the last of of which entered Petra’s face through her nose and traveled up through her brain to the back of her skull.

But miraculously, Petra survived. And it's all thanks to an extremely rare brain defect she didn't even know she had. It turns out Petra has a genetic defect that causes a small amount of brain fluid to flow from the front of her brain to the back, and it was because of that fluid -- combined with the way the bullet hit -- that she's lucky to be alive today.

Instead of ripping through her brain, the bullet traveled through the fluid, which channeled it away from hitting any of her brain matter.

Because the brain defect doesn't affect her brain function, Petra probably would've gone her entire life without even knowing about it if the shooting hadn't happened. And although the bullet is still lodged in the back of her head, she's alive and expected to make a full recovery.

Despite the good news, Petra still faces surgery and possible facial reconstruction. That’s where you might be able to come in. To donate and help with Petra’s medical costs, go here