The role of Annie, Ben's childhood friend, was portrayed by
Madeline Carroll. She appeared in the Season 3 episode,
"The Man Behind The Curtain".
Annie appears with young Ben Linus on the Inkworks Season 3
trading card "Always Together". The card is foiled and die-cut
from the chase subset, Ties to the Island.
I have also written to Madeline Carrolll, requesting an autograph.
I'll update this post if/when I receive a response.