Hello, everyone

This is my first post here, and I need some sizing help for the spitfire. I'm 15 and about 5'11 and around 70-75 kgs. I'd probably say i'm an intermediate surfer, i live on the Sunshine Coast and usually surf anything from 1-7 foot It's usually pretty crappy though. I've been looking at the 5'6, will this be to small? I've been riding a 6'0 futura which i recently broke, it seemed to have more than enough float.
thanks