Sunriseandsunset Stories

Angels fly high in the sky once they sprout their wings at the young immortally celestial of 8, but one started earlier at a mortal age of 10, and was stuck behind with the other angels because she wasn't born in that world originally, and neither was her human sister....but now she's 13, and her human sister 12. What are they gonna do now as they find out their true heritage and try to cope with their current situation?