Dahlia Gruen will always remember her 10th birthday — Sept. 11, 2001. In the years since, she’s worked to reconcile her birthday joy with the mournful spirit of the day. A few months after the attacks she created the website BirthdaySpirit.org for “9/11 babies” to come together to swap stories and find comfort. BirthdaySpirit offers suggestions for reconciling celebration with grief — like bringing a birthday cake to firefighters or lighting an extra candle to honor the victims. Gruen, a first-year student, said she will continue to maintain BirthdaySpirit while studying human development and psychological services.