Size is fine but learning on a bigger board is easier.

Ideal board size is "if you measure from your armpit to the ground" is what Dan from Cardboards once said, he has been right ever since. If you are 6' then a 135 should be will keep you out of trouble as i'm 6'4" and mainly ride a 140 Tempo. (one of many boards)
Some people like smaller boards but then it is a compromise with a bigger kite.

How many people are now standing next to their board measuring???

I started from day 1 with a slighshot chrisis 134 and had no problems whatso ever.

On a more serious note I'm 6ft and 70kgs and ride a 129 try out a few different sizes and types of boards (if you have a store thatll rent kit to ya) and buy the one that you feel most comfortable with

And for the love of everything that's good don't get a board leash