I still say it would have been more interesting to see an ‘older’ Supergirl and a ‘younger’ Power Girl in the Nu52. She’s Kryptonian, they kinda live for a long time.
This Kara is only slightly younger that Clark, with her father’s keen scientific mind who doesn’t eye to eye on Clark’s non-interference ideals, and would rather share Kryptonian technology with her adopted planet. It has been argued with Clark more than once. She’s a bit of an explorer, so she wears universal translators (things in her hair) to travel the stars when she can, or to simply get away from her cousin after a meeting of the minds.