So, you know a lot of things for being so new to the sport. Yes, rockered skis "ski shorter", but this design in the V5's skis long. The contact points with the snow are really close to the tail and tip
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Dear Lord, stay away from skis older than 5 years old. Technology keeps improving, particularly bindings, which are a safety issue. But also performance.
If you choose these V5s, and want them to last a while, I would go for the 177 at your size. Because, to
@François Pugh 's point, the ski itself is medium flex, but you are at the top percentile of size (particularly height), so you will tend to overpower it once you get, say, ~20 days under your belt (give or take). The 170 cm would be a little better to start.
(In a given design, and for the same skier) A shorter ski is easier to control, and a little easier to bend at lower speeds (bending that camber center point into the snow is what makes a skier turn efficiently). But for the same skier, when she is going faster, it will be less stable at speed, for a number of reasons. So, short == nimble and softer, and long == more stable and stiffer.
Also, there is a ton of skiing still out there, this season. Now that you became a family of skiers, you might find yourselves doing spring trips to fun locations (spring skiing is best, particularly for the little ones!! no cold, long days, blue bird days, what's not to love)