» Sat May 28, 2011 2:54 am
Well, in Fallout 3 Carol, the ghoul who ran the inn in the Underworld was young when she was exposed, but I don't think she said how old... She was with her father though, and it is implied she was a teenager I think. Underworld wasn't formed by ghouls, but rather by survivors of the bombings who gathered there and gradually ghoulified. Carol seems the only pre-war ghoul left there though.
Desmond in Point Lookout was also pre-war, but apparently an advlt. We don't know how long it took him to change though. Moira seems a freak case, ghoulifiying almost instantly after Megaton explodes when she was nearby.
On the other side, in New Vegas, an entire NCR town turns to ghouls after a radiation spill. That happened fast enough that, even knowing it happened, the soldiers stationed there couldn't escape fast enough to avoid becoming ghouls.
So it seems that it can take anywhere from maybe a few hours to weeks or months for a person to become a ghoul after becoming exposed to high radiation. What other factors that make some people turn into ghouls while most just drop dead are unknown...