How old is Reya Mantlemorn during the Descent into Avernus adventure?

Question

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?

Answer 1

She is somewhere between 13 and 19

Given the fact that she is described as a teenager, that puts her somewhere between 13 and 19 years old (according to the generally agreed-upon definition of a teenager). Understandably that's confusing when she is referred to as a veteran, but keep in mind:

Stat block titles are a convenience, and not necessarily a job description

The fact that she's given the stats of a "veteran" doesn't necessarily mean she has earned the title, it's just a convenient shorthand to point to a block of stats. For example in Waterdeep: Dragon Heist (the only adventure book I have handy), Urstul Floxin is described as a "glorified thug" in his flavor text, but instead of a Thug stat block his stat block points to a different archetype:

Urstul Floxin is an Illuskan human assassin, with these changes...

Stat blocks often match the character archetype, but some variations are possible, so take any Stat Block titles with a grain of salt.

You can choose what makes sense in your adventure

Given the age range of 13-19 you could make her 19 and still describe her as a "teenager", with 6 years of dedicated training under her belt to account for a CR3. You could just as easily have her in her mid-teens and attribute her high CR to her deep resolve, faith and determination, like for example Joan of Arc. If it suits your story, she could be 13 and have been trained from the age she could lift a sword, arriving in Elturel already capable of taking on a party of 3rd level adventurers- much like the character Hit Girl from Kickass.