well a 17.8 but a rocket also isnt a typical shape a little fuller but I would say no esp if you arent really used to a shortboard. that is a nice looking rocket though on nynj surf. I do know where for a 75 bucks more there is a brand new 5'8 fletcher f4.
I ride mostly fishlike shapes but have been riding a mini-simmons style board that is 5'5" . These are really wide boards though so that makes up for a lot of length. BTW I weigh in at about 200lbs more or less and am 6'1" tall.