Buying a wakeboard is no easy task, it's like buying a car without driving it. Every wakeboard has their individual pros and cons.
My advice would is to buy used, cheeper in case you realize that you dont like the board or dont like the sport in general.
Sounds like my brother and you weight about the same... with that, and I kid you not a year and 1/2 ago, he had never wakeboarded in his life, let alone gotten up on waterskis. Todate he's able to clear the wake with a few grabs, and do some surface 180s.
The board he rides is an '05 LiquidForce Substance 142 w/ '05 Sphynx Bindings, not the cheepest set up in the world, but in the long run well worth the money.
Sorta long winded but I hope this helps