Amber Tamblyn was 21 in The Sisterhood of the Traveling Pants when she played the character 'Tibby Rollins'.
That was over 19 years ago in 2005.
Today she is 40, and has starred in 29 movies in total, 21 of those since The Sisterhood of the Traveling Pants was released.
In The Sisterhood of the Traveling Pants, I think Amber Tamblyn looks: