As as matter of routine, no. Nor, would I read it out of curiosity. I am a big fan of privacy.
However, I am her mother, and I am responsible for her welfare and her actions. If there were any indication that she were in serious trouble, danger, or bringing harm to herself; and the answers might be inside.........yes, I would.
It is my duty to protect and guide her. That duty surpasses the privacy of a child.