Wouldn't the change from tall to short later in life be sort of unrealistic? I mean, while it is possible to be a tall child and suddenly stop growing as a teen, reverting from being a tall teen to short adult is a little less probable.
Tall for a 13-year-old is pretty different from what's considered tall for an 18-year-old. It isn't too uncommon for someone to be the tallest kid in their class at that age, but totally stop growing from there and ultimately end up being shorter than most of their peers later in life. If you're talking about going from 18 to 23, the change between those ages will be handled differently.