Does she still have family among the refugees or in baldurs gate? Joining in with a bunch of tadpoled weirdos on a quest to the underdark would look slightly less unappealing if she had nowhere to go.
As I understand Alfria's story, she implied that all she cared about was her (music) teacher, and she was killed. I hadn't noticed anything beyond that about Alfria's background. Mainly because I think she focuses on her teacher a little too much. It seems it was more than a standard student/teacher relationship based on the way Alfria is mourning the teacher's loss.
