Maria Ppoino!

From kodanclub.com:
Soon after entering junior high school, Hinata Abe is hit by a truck, but survives with only minor scratches. This earns her the nickname of “the Miracle Girl” at school.
Hinata has a creepy dream the night after she leaves the hospital. She awakes to find her room filled with flames and smoke. When she cries for help, the Virgin Mary appears before her! Mary explains to Hinata what really happened to her: Hinata actually died in the accident 3 weeks ago!
A series of mistakes stopped her soul from going to heaven. Mary tells Hinata that she is dead and it cannot be changed. But Hinata pleads for her life back. Mary agrees to offer her a chance on one condition: Hinata must save 12 lost sheep within 100 days. She starts her mission to regain her life, wearing a pendant given to her by Mary.
A miraculous fantasy love story begins.