Oscar talk begins

"Oscar talk is already all-year round (as if you don't know yet!), but it seems to me, the focus remains on the established performers - most notably the filmmakers and the lead actors and actresses (Streep, Dench, Day-Lewis, Eastwood, Scorsese).

Jennifer Hudson won the Best Supporting for Dream Girls at 25,
while Anna Paquin won the same award for The Piano at 11, one of the youngest ever. Nominees include Natalie Portman (Best Supporting for Closer when she was 24), Soairse Ronan (Best Supporting for Atonement when she was just 13), Keisha Castle-Hughes (Best Actress for Whale Rider when she was just 13), Ellen Page (Best Actress for Juno at age 20), Abegail Breslin (Best Supporting for Little Miss Sunshine at 10), Rinko Kikuchi (Best Supporting for BABEL at 25, the year Hudson won) and Keira Knightley (Best Actress for Pride and Prejudice at 20) to name a few.
Heath Ledger won the Best Supporting (Posthumous) at 29, but he was 27 when he got the Best Actor nom for Brokeback Mountain. Nominees include Ryan Gosling (Best Actor for Half-Nelson when he was 26), Jake Gyllenhaal (Best Supporting for Brokeback Mountain when he was 25). While he's over 30, Adrien Brody won the Best Actor for The Pianist, when he was 29, the youngest ever to win".
Source: themovie-fanatic.com