I have a process for traiting sims that you may want to try, or just randomize (weee!):
Toddler trait: Randomized. I call this their "innate" trait. They're born with it and will dictate the rest of their life. I do not ever respin the trait, no matter what I get (even fussy).
Childhood trait: Chosen. I use either the Innate trait to choose the childhood trait OR their top skill if it's really lopsided. For example, an angelic toddler may get the trait good or cheerful whereas an independent toddler may get the self-assured trait or conversely a trait that is meant to denote being more of a loner. A toddler that maxes out on social but not any other skills may get the outgoing trait.
Teen trait: Randomized. I call this their rebel trait because it's not based on their parents or their innate trait. It's completely random and is part of them growing up and figuring themselves out. I never change or re-roll this trait UNLESS it somehow contradicts the innate trait or their attained skills. (A max in social skill is not getting socially awkward if it rolls to that).
YA trait: Chosen. I call this their Hereditary trait because as people get older they tend to turn into their parents or just pick up their parent's habits. I choose one trait that is from either one of their parents. If their chosen childhood trait or randomized teen trait was already a hereditary trait, I choose something based on their acquired skills, aspiration, likes/dislikes etc.