The girl's colors are so similar to the surrounding scenery. She is also wearing white, without shoes, and in a very casual stance. She looks almost irritated. She blends in so well to everything else, it is like she is fading away. Perhaps she feels disgusted, unnoticed, and bitter, and is about to jump off the cliff in suicide.
The mirror could have been easily larger to accommodate her entire head. However in the painting the majority of it is her back and the crown's entire front is hidden to us, save only for a fraction seen in the mirror. We have a candle as her only source of light in the room, positioned directly next to her face, and the room is very dark. The girl looks to be about to cry due to her puckered chin.As explained before, the grandeur of her outfit and headpiece is obscured to us due to it's limited visibility in the painting. This reflects the uncertainty of her position she may feet at the moment...perhaps she is about to be married off, or enter into a high ranking postion, and she is reluctant. The only part of her we see completely is her face and neck, and the candle is metaphoric for her desire for clarity here. Her shoulders are exposed, which, for this time period, is almost nakedness, and they are graced only with her hair and her pearls. Perhaps she is feeling vulnerable and is fervently questioning whether wealth, beauty and grandeur will offer her security and comfort. Lastly, we actually are seeing two people in the painting. Which one is the real girl? Is it the one with the beautiful outfit or the reflection having most of it hidden except for her face? Is the reason we see more of her back beacuase she wants to be the girl in the mirror? Which one is real?