The Sims 5 Zodiac Traits

Zodiac signs in the Sims 2 were basically shorthand for personality types. You could assign your sims personality points (e.g. 6/10 playful, 3/10 neat, 7/10 outgoing, etc.), and the game would assign the sim a zodiac sign based on that, or you could pick a zodiac sign and the game would populate personality points based on that. They were not two separate things. Once you created the sim and put them in the world, their zodiac classification would influence the sort of sims they were attracted to.

The zodiac signs in Sims 2 actually had nothing to do with when you were born. Twins would have different zodiac signs if they had different personalities.