FORT GREENE In the nearly pitch-perfect, autobiographical film, Tiny Furniture, by newcomer Lena Dunham, we meet a young post-grad navigating life after college. Dunham stars as Aura Freeman, a wry, often amusingly grouchy, and talented twentysomething who is living with her (real-life) mother and sister while learning how to be an adult. The dialogue is quick and witty without being cloying or obnoxious, and even when the conversations verge on narcissism, the indulgence seems natural to the self-professed entitled characters. Jemima Kirk manages to steal every scene she is in, as an anti-social art-world socialite with a trust fund. Lena Dunham’s own acting is slightly uneven, but she is goofily charismatic enough to make her occasionally stilted delivery seem winning. The film opens tonight at BAM Rose Cinemas.