This story is a sequel to The Life of a Non-Brony
Before the bat pony filly Comet Screech was adopted by TD Powell and his wife Cheerilee, She lived for several years in a Canterlot orphanage. Every day is a crushing reminder that her differences means that she is unlikely to be adopted, and as each day passes and she gets older and older, the chances become even slimmer.
She'll never get out. She'll age out of the system. She knows it. Nopony would want a freak like her...