Does the age of 12 refer to at the start of the game, or for the most part of the game? The time interval between the two visits to Mt. Vaal is definitely at least two years, judging by the progression of seasons in the cutscene
BlueLionheart - "Be careful, dear friend, lest you fall into the endless ocean of stars..." - 水風死 TALK - 01:33, November 29, 2009 (UTC)
If I remember correctly, the twins were nine when they visited the mountain the first time. The second visit was when they were twelve.