In Baldur's Gate: Descent Into Avernus, on page 31, the character Reya Mantlemorn is introduced. The boxed text describing the scene in which she is introduced includes the following:
A cloaked figure approaches, armor clanking with each step. One gloved hand rests on the hilt of a longsword. The other pulls back a cowl to reveal the face of a teenager with brown skin, red hair, and a haunting gaze.
Below the boxed text, this small piece of trivia about her is relayed:
Born in the land of Turmish, Reya came to the holy city of Elturel to train as a Hellrider when she was twelve. As a faithful follower of Torm, Reya is prepared and has trained to sacrifice herself for the greater good.
However, as far as I can tell, the rest of the book does not at any point state how old she is now.
Given that her stat block is of a
veteran (with a Str score of 16)
a significant number of years surely must have passed since the age stated in the second quote above and now, otherwise she's damn strong (not to mention skilled and experienced) for her age.
How old is Reya Mantlemorn during the adventure?