Trying to remember horror movie from when I was a kid

[HauntedMovieHunter]

So the movie goes like this if I remember correctly.
Girl got mirror that is possessed by some demon/devil
She gets sent to a nun type church place where bad stuff starts happening
Such as a nun being murdered by a stain glass window that came to life
Also the girl dances with said demon/devil in one scene about all I can remember... An help at all would be great
was from early 90's when I saw it..

[retrorussell]

Maybe one of the MIRROR, MIRROR movies.