You were a guy for 16 years, you live with your powerful girlfriend, she was very strong in magic. She also hid from you the secret that she could become a huge snake that could eat an entire rock, and she successfully hides it from you, and you were a boy who just studied with her and was her young guy, you were very weak compared to her. You lived in a big mansion and your girlfriend was very rich and created a huge magical forest around the house.