I don't know your skills, but if you already are going upwind or can control the kite, go small.
There is no need to get a board bigger than 160 cm. You could be able to have lots of fun with boards like 140-150cm.
They start early and are so much fun to play around with.
Guys nowadays are lucky when starting, they have all this nice gear available, while I was using these damn directionals (
End of last year I switched to TT in wakestyle and they work great!
Carving, jumping, going upwind, fast moves while jumping are no problem.
Now I ride an X-Shooter, which is a new brand, but excellent board.
have a look at http://www.x-shooter.com
Hopefully soon I will have new pictures of me riding with this board.
So, don't go too big, it would be a step in the wrong direction!