Perhaps I should explain the generally conservative recommendations that I make in most cases regarding ski flex and length choices.
I have made my living selling skis for most of the last 37 years. During that time, I have listened to many many questions like this one, heard the skiers describe themselves, and then in several cases, seen them ski.............
People usually, overstate..........their need for speed, agressiveness, depth of powder they ski, and average days on the hill. They usually understate...........very little.
So when I consider a size suggstion, I try to evaluate how well a skier skis and how agressive they are from incomplete and possibly imperfect information. In the case of this thread, we have a skier on the shorter, lighter side of average who has been accustomed to a light, (some might say wimpy) ski in a very short size
. It is best for that skier to understand what the tradeoffs are between two length choices. This is especially true when one is making a major
jump in size, width, and agressiveness.
It is axiomatic that a longer size will be more stable and provide more lift in truly deep snow. This usually sounds good.
OTH......it is often forgotten that the longer ski is also often a stiffer ski. These factors means that it will usually require more speed or more muscle power to turn it.
So, while a longer ski may be better in 10,20, or 30% of the conditions, it will generally be more work in the other 90,80 or 70%. I'm not suggesting one way or the other, but merely emphasizing that ski length, like width and stiffness is no free lunch and there are always compromises.
Everybody has to accept those compromises one way or another.