How old is your daughter, and do you know her torso length? I'm not sure even a small G4 will fit a small female. My daughter, now 17, still has a very hard time finding a lightweight pack that fits properly. My lovely wife spent a couple of years trying on every UL cottage gear pack out there, trying unsuccessfully to find one that would properly fit a female-type person. (The vast majority had shoulder harnesses that were far too wide and set too far apart, and dug into her neck and chest.)

My daughter recently got the REI 45 liter women's pack on sale. It seems to have enough torso adjustment to fit her well, and the hip belt pads don't meet in the middle around her waist (yay!). We'll see how she likes carrying it next month.