Alien Girlfriend

Hello, this is my first posted story so it will be far from perfect but please bear with me. This is a story about a guy named Jake and his girlfriend Katy. The story begins with Katy confessing to Jake that she is actually an alien that came to earth for research. I would like for this story to be different in that all the NBM will be at the beginning of the Story as different choices and then the rest of the story will explore the day to day life of that transformation. So, if you do add, please refrain from making the story convoluted or messy, thank you.