If she's a novice, she probably doesn't know what kind of skier she wants to be. I'm 5'8, 120# and began on short little thingies like 150-154. Hated the length. I was inclined to be intimidated by a longer length (ski shops see "female" and assume they want something "easy" to handle, and stupid me, i listened...), but tried out the 160-165 length as a beginner and loved the stability a longer length gave me. I only learned that after spending some $ on shorter skis which I fairly quickly didn't like. I routinely ski 170-180+ sizes (almost ALWAYS "men's" skis since somehow the industry has decided that we women don't want speed or stability...)
I think too many women listen to "advice" to go shorter, or stick with women's skis, because of misconceptions about their abilities, desires, and style. When I go to demo, for instance, I usually can't demo women's skis...because they only offer them in short lengths.
I would have her demo something in a shorter and in a longer lengths before going through the motions of buying her something. I don't know if this is gender-specific, but I notice a tendency for female skiers--esp novices--to find the "perfect" ski and assume/decide that this ski is "it" for a really long time. So if you buy her something that isn't going to let her grow, she may stick with it long after its use, which can hold her back.
Maybe that's just stupid advice from me...i haven't had enough coffee today and my brain gears aren't all meshing.