A number of Jenny's scenes require her to be in a certain part of the house. If she's not where you need her to be, try again the next day.
Jenny's storyline has two conclusions, based on the choices you make at key points — marked as either dominant or submissive. These choices affect how Jenny treats you, but won't lock you out of completing the storyline.
In the morning, exit your room to enter the upstairs hallway. There's a chance you'll hear the shower running, meaning Jenny is out of her room. If not, wait until the next morning to try again.