Maybe, the story starts with the reenage girl falling in love with some guy (let's call him Tom)Somehow, Tom gets in mortal danger in the real world. She's scared to go and help him, and then a prince who looks somewhat like Tom appears. The girl (Let's call her Jen) has actually fainted and is dreaming. After a long adventure with the prince, she wakes up, and only seconds have passed. Now, she is brave enought to rescue Tom, and they live happily ever after!(sort of)


You see, in a story, it has to change the protagonist's life in some way. If Bob protagonist learns nothing and accomplishes nothing (and neither does anyone else) then it wouldn't be a worthwhile story.
You don't have to follow my ideas, but the dream should inspire the girl to be less shy, ask Bob out, etc. or something like that, perhaps even make her start looking for an actual prince-leading to a sequel. Or that might be a prequel.