Why would Fred have been told to expect an 11 year old boy?

In S02E01 of The Americans we are introduced to Emmett and Leanne Connors, another spy couple similar to the Jennings. Both families are with their kids at an amusement park/fair sort of place.

Emmett Connors is supposed to do a brush pass with Fred, in order to obtain information from him. However, he is being tailed and discreetly pulls Phillip aside and tells him he needs to do it. Emmett tells Phillip that Fred is expecting someone in a blue hat with a 11 year old boy... However, while Henry Jennings is supposedly around this age, Emmett's son Jared is definitely not. It's mentioned a couple of times that he's going to Carnegie Mellon the following year, which would make him a high school senior (approx. 17-18 years old).

Presumably, Fred would have been told these instructions in advance. Much earlier than the Connors had discovered they were being tailed. This assumption could be completely incorrect though, which could make sense, but I didn't see any evidence in the show, so it's still just an assumption.

Why would Fred have been told to expect someone obviously younger than Jared? Was this just some sort of oversight by the writers, or is there some detail I'm missing?