I'm 5'9 125 lbs and I'm looking at buying a pair of 181 pipe cleaners from a friend. I was just wondering if they're to big? And if they will restrict me from doing anything
No they're not too big. Bigger skis will make you a stronger skier. Only thing I would be wary of is that they are a stiffer pipe ski, not a buttery park ski, and you are pretty light to start with so they might be stiffer than what you are used to.
It's preference. Some people like short skis, some like long. Doing things like rails and butters will constitute a short ski, whereas charging lines and cliffs will constitute a longer ski.
if you are still growing they'll be fine. They will feel long at first but if you can learn how to ski them i guarantee you you'll probably never go back to a shorter ski