
She's cursed, just like the teacher/gramps friend. She cannot grow up, stuck forever in a child's body.
She was manipulated by others, as her mind also suffered from the curse, she's like, an adult/teenager (if I'm not wrong) who's been stuck and treated as a child for her entire life.
After everything comes to light, our Aerin breaks Yellow Aerin curse, this way, she'll be able to grow old, make genuine connections and be happy as herself.