I'd make sure any Rev for someone that size (smaller body and weight) has enough brake in the settings, especially if the wind is up... There's a balance of course, you want enough forward so it's easy to launch, but not so much that they get jerked out of their shoes.
Ian Willoughby, Alex Mason, Joe Loranger, all started Rev flying when they were a similar age.
Wrist strength and hand size are also factor for leverage on the handles.
Some good discussions on the subject (and many more with a little browsing)...http://www.revkites.com/forum/topic/4409-my-leaders-your-thoughts/http://www.revkites.com/forum/topic/3152-do-you-adjust-knots-on-top-or-brake-line/
The EXP is a fine start, as is a Rev II (or B2)... But you might need to whip up some leaders.