Life goal for an adult - I want to perform as much Show Jumping on a Horse as possible at the Stables!
Here you need a 3-star horse to be able to perform show jumping. To unlock the 3-star horse you first have to complete the full collection for both the horse trick hobby and the horse vaulting hobby.
Go to the stables on the map and call your sim here with the whistle. Click on the 3-star horse and select the option Show jumping.