My son is now 12 and is at the jumping stage, he learnt on a Switchblade I 5m and now has a quiver of Switchblade II's in 4m and 6m. These kites have been really good and helped his progression enormously. Can't stress enough how important an easy relaunch and "drop-the-bar" depower has been.
He is a bit over 40kg now and riding an Underground FLX 124, he switches to the 4m when the wind is steadily over 22knots.
pics here
www.seabreeze.com.au/Media/View/12194/Kitesurfing/Tai-Lewis-riding-Magnetic-Island/http://www.tevenei.com/tvm/nellybay_kite_forecast.htmPersonally I'd steer away from the DNA unless you are going to be learning in winds 18knots +. I've watched a couple of light (55kg) learners at our local beach struggle to relaunch the DNA 9m in 12-14knot winds, while the SB's are popping off the water easily.