I think she's probably thinking about her past memories, maybe when she was a teenager, thinking that she will be or wont be a certain type of adult, and now she's reflecting that maybe life is not that simple and that adults make difficult and complicated choices....

I love the shadows and light play, @djacbaweur :) The pose is also lovely and the room's moods is captured well with the use of framing and composition <3 Beautiful picture !