Sharon was Amy Pond's aunt. She was originally Amelia's guardian, becoming so due to Amelia having lost her parents to the crack which erased them from existence, creating an alternate timeline. In this timeline, Sharon moved with young Amelia to Leadworth sometime prior to Easter 1996. (DW: The Eleventh Hour).
In an alternate timeline in which all the stars were destroyed in 102AD, she took Amelia to the National History Museum in 1996, where she dragged her around it until Amelia ran away and found the Pandorica, a prison box of legend. After Amelia went into hiding, Aunt Sharon looked for her, but ultimately failed.
After the universe was restored and the cracks in time were closed, restoring the timeline, Amy's parents were restored to the timeline and Sharon never became Amy's guardian. Sharon attended Amy's wedding and witnessed the return of the Doctor on 26th June 2010. (DW: The Big Bang).