DD16 did it a few years ago and had a blast. It was exhausting, but she felt like a star when she was able to stand on the board and ride it in a few times. I thought the team that did the instruction was tremendous. Two of them were in the water with the newbies and must have been treading water for 60 - 90 minutes.
Anyway, it was a great experience. Getting up early is a pain, but it is really cool to see the park completely empty.