Jon,  if she is well-controlled it may not be a problem...I’m an adult with SW CAH, 5’2" and usually about 105-110 lbs.  The only exception was when I was oversuppressed and ballooned up to 140 lbs.  Once I fired that doc and got a new one, I lost the weight over the course of about a year and went  back to my normal weight.  I am lucky in that I can eat what I want to eat. 

One thing I would recommend (as do most dieticians) is not to fall prey to the "clean plate club"  I eat only when hungry, and only as much or little as I want.  Anything left on the plate will not feed starving kids across the world no matter how much you try to tell your child it will.

Betsy