Replying to What Park Ski

I'm thinking about getting Line Afterbang 2015 for this year in park. I'm 15, 5'8, 135lbs. This is my second year skiing park. My first year I used Volkl Alleys 2013, 158cm. They were +4cm up(recommened for freestyle), not center mounted. I don't know whether or not I should get 166cm or 172cm. I don't know the mounting spots on the ski, i just want it to be on, or close to counter mount for park. I ski park like 90% of the time. I don't think i'm going to grow much, i'm like 1-3cm taller than my dad, just as tall as my brother, maybe a hair shorter. I'm an agressive skier, i've pretty well with rails and boxes in park, as well as jumps. I'm going to be using Marker Griffons '15 for the bindings and Full Tilt Drop Kicks for boots. I'm going all out this year and i'm going to be using this skis for 2 seasons. Thanks for the help.