Going to a children birthday party

Today, we are going to a birthday party. The one of twin brothers, the children of one of my wife's acquaintances, whom she met in her mother groups. They are three. It is the first children birthday party we have been to since August last year. I thought it was going to be something we do far more often now that we are parents. Apparently not. I'm always both excited and anxious to see our little Wolfie interacting with children his age (or thereabout), especially in a party environment. Will he be sociable, will he be shy, aggressive? I wonder if he will enjoy it.