171 vs 166

So I've always ridden 166 size skis, they go about up to the bottom of my forehead without shoes on, but I feel like when k grab it takes a bit more effort to reach, also when I see it in video it looks almost like the skis are too short, not south style. Lol obviously styles in the skier but ya know what I mean? Idk, I've ridden the 171's but honestly it really felt very different. How hard is it to get used to a new size? And how hard is it to learn the spin and weight again?