That was over 10 years ago in 2012.
Today she is 38, and has starred in 9 movies in total, 6 since Arbitrage was released.
In Arbitrage, I think Brit Marling looks:
Arbitrage scores 6.1 out of 10 on The Movie Database.
Brit Marling's first acting role was as 'Maggie' in Sound of My Voice, released in 2011 when she was 27.