What skis should i buy??

So heres the deal, im growing rapidly and I don't want to buy a nice pair of skis cuz ill just grow out of them in a year so for the past two years ive bought a shitty pair and im doing the same this year... I just cant decide on what size to buy, Im about 5'10 120 as of right now, I prefer a nice light shorter ski and ill be skiing 80% park, 10%deep off piste pow and 10% screwing around groomers My size choices are 156, 166, 176 any suggestions on what size I should be wearing are good