I think clem would be any awesome character regardless of her age, she seems more sensible than most of the adults, and is way less argumentative. But she can be assertive and knows what she wants. Most importantly she isn't create masses of needless drama like most the other characters.
She does seem a bit ridiculously mature bordering on "Mary Sue"-ism though and her repeated need for rescue gets a touch obnoxious (though that may be resolved soon).
I think she's a straight up good character, not just a good child character.