Time Traveler's Trilogy Series by Paula Ottoni

Lucy Hernandez has not been a normal teenager since she discovered the meaning of her birthmark, shaped as a half moon. She can travel through the eras, and together with her Time Traveling instructor, Mr. Harris, she has to do her best to maintain the past the way it is supposed to be – the way it has always been. But when a young Time Traveler knight plans to change a previous time in his own benefit, preventing his older brother to be born, Lucy and Mr. Harris will face a lot of trouble... moreLucy Hernandez has not been a normal teenager since she discovered the meaning of her birthmark, shaped as a half moon. She can travel through the eras, and together with her Time Traveling instructor, Mr. Harris, she has to do her best to maintain the past the way it is supposed to be – the way it has always been. But when a young Time Traveler knight plans to change a previous time in his own benefit, preventing his older brother to be born, Lucy and Mr. Harris will face a lot of trouble. She’ll have to be braver than ever, especially because she just happened to find out she fell for the victim… and there is no way to be in love with a guy from the Crusades and not mess with Time. less