Wings of Darkness by Sherri A. Wingler

Death comes for everyone eventually, but Izzy Maitland plans to live forever. At nearly eighteen years old, it's not an unreasonable goal, but Fate has other plans. Izzy has a car accident. A bad one. Suddenly, strange things start happening and her ordinary life is turned upside down. She wakes up tasting blood, more often than not, and her injuries heal at an alarming rate. Her friends and family weaken, and every day, Izzy grows stronger. Strangest of all, she seems to have acquired a stalker, and he might be the Angel of Death.