A Rhapsody with the World After Being Turned by the Vampire Queen

The protagonist's true identity is a little vampire princess.

This is a world where magitech, swords, and magic coexist. A twenty-year-old model citizen from Earth transmigrated into the body of a knight and became an eighth-rank knight before turning twenty. It was the standard protagonist setup. So why did I turn into a white-haired, red-eyed vampire girl the night before taking part in the contest for the Holy Sword?! (She turns into a loli in Chapter Six. I know you like reading that, but please read the first few chapters for the sake of the story.) After the protagonist leaves the human empire, she stops hiding her true appearance. While she is in the empire, she can only conceal her identity. After all, she's a holy knight, but her true form is that of a vampire. If anyone finds out, it's over.