The Once Seen But Never Mentioned

(Y/N) is a young 12 year-old girl, youngest sister of Katara and Sokka. She is the second waterbender in her village besides her older sister, although (Y/N) was younger she is very skilled at her waterbending. Both sisters teach each other when practicing. (Y/N) escaped home when she was 9 years-old, along the way she discovered that she can master the other 3 elements and made friends along the way. Although she may have liked her journey she missed the village and her siblings. Once she had returned to her home, she can't help but to think "Am I the Avatar?". Soon enough 3 years have passed since (Y/N) had escaped the southern water tribe, and discovered her other "abilities". She has been practicing her other abilities in secret and thinking her possible fate but everything changes when she and her siblings found a certain airbender. What will happen next? Will (Y/N) be who she thought she was? or will she be the once seen but never mentioned?