Is it normal that i have this unusual fantasy about a girl i like?

There is this girl in my class at school that looks so cute, I stare at her all the time. I try not to but I can't help it. When I'm staring at her, my brain creates a fantasy about her. I envision myself in a pet store and there is a pretty golden birdcage hanging in the window of the pet store. Instead of a bird inside the birdcage, I picture the girl inside the cage instead. She is wearing a tiny little bikini but nothing else and is sitting on the swinging perch as though she's been there forever.
In my fantasy, she begs me to let her out of her cage. She says she's a human girl, not a pet, but I tell her to deal with it and that the cage is where she belongs. And she swings sadly on her perch as people pass by the pet store and look in at her. Anyway, it's a weird fantasy. Is it normal?