I'm like 5'5 and around 120lbs, I've been this size for a while and I'm 19 now. I actually ski chronics, but 166cm, although I totally could move up to 171 or whatever they come in now. So short, skinny and not growing like you. I've been skiing for a while so I'm a pretty good skier.
When I went to colorado and rode at loveland I rented JJs like twice, only rockered pow ski I've ever ridden. I believe I rode the 185s both times and they were fine, initially I thought they were gonna be a bit big. I actually had one of the best tree runs I've ever had on them (aka like 1 of 20 ever). They were easy to smear around tight turns in tight spots, from the rocker I guess. I had no problem with carving them on open slopes or controlling them at all. They definitely ski shorter. They're a ton of fun on packed snow, they butter nice if you lean over the rocker. So I'd say go for it. Go a bit of pow on them too, obviously they float. The do get sketchy going mach 10 down chunky stuff, but that's expected.