I mean it's not like buying skis would be bad. I just don't think you need to. It'll be hard to find a ski in the length you are looking for that's a pow ski. The shortest most of them come in is 169, unless you want to look at woman's skis. Since you aren't very big you can get away with a ski that's not truly a pow ski, though. Personally I would suggest
these skis. The are a decent price so it won't be the end of the word if they are too short after one season and the bindings are easily adjustable to account for growing feet (if you do get two seasons out of them you won't have to get them remounted.
Just think about if you would rather have an okay setup now or a really sweet one a few years down the road when you are done growing and actually need really good equipment so you don't do things like blow your bindings up.
Trust me, I know how it is to live in the western US and ski on a not powder ski. I'm from Seattle and it dumps in the Cascades and I still grew up on rental skis. When you stop growing get a legit setup and spare no expenses because it's worth it. For the time being if you try and save money you'll be able to get whatever setup you want.