Are children reincarnated as adults?

I was considering porting a character from an earlier edition of the game, who had been reincarnated before becoming an adult. This is purely backstory, however it got me thinking about how this would work in game.

I don’t know if the spell changed between editions, or if I had missed it entirely but the wording now makes me wonder how reincarnation works when reincarnating non-adults?

You touch a dead humanoid or a piece of a dead humanoid. Provided that the creature has been dead no longer than 10 days, the spell forms a new adult body for it and then calls the soul to enter that body. If the target’s soul isn’t free or willing to do so, the spell fails.

Emphasis mine.

Do infants/children/teenagers get reincarnated as adults? Are their any in-game ramifications?