I've not tried this option myself but the sims have to be EITHER friends, bestfriends or "friends forever" for this to work (I can't remember which on e it was)
I had 2 BFF's, 5 best friends and a few others that were just regular friends. When I aged my guy up I didn't get the option to age anyone else. I tried aging him with the birthday cake and just letting him age on his own, neither of which allowed any of his townie friends to age.
I don't think I've got any aging mods that are directly preventing this action but I really don't know, I saw someone else with the problem and thought someone might have found a fix for a similar issue. It's not that big of a deal though, I can just age them individually it'll just take a little longer.