What about the reverse- who was the youngest to win an Oscar for screenwriting?

I can think of a couple of exceptionally young writers- Harmony Korine wrote Kids at 19, I think. 15 year old Nikki Reed co-wrote Thirteen with Catherine Hardwicke.

Any others you can think of?

Mr Scott is absolutely right.

Age doesn't matter. John Singleton was 24 when he wrote Boyz and the Hood. Paul Thomas Anderson was 27 when wrote Boogie Nights.

Matt Damon and Ben Affleck were 25 and 27 when they wrote Good Will Hunting.

Write a Great Script.

if Mark Boal was 37 when he won Oscar for Hurt Locker, I can't imagine at what age he started. I just start to determine to be a screenwriter from zero, and I already 25 years old..