You should be/have been an only child. Turns out you prefer to have your parent's complete attention and you dislike all the background noise that would go along with other siblings.
You would be a great sibling to one other child. You enjoy the companionship of a sibling, but would dislike the drama of more than one sister or brother.
You would have them and they would have each other when you opted to be alone. Less than two siblings would make for an awfully quiet house, which would drive you crazy, however more than two sibs would cause you to get completely lost in the fold and that would be unbearable for you.
You love the energy of lots of people and would enjoy interacting with multiple siblings. There is a limit on how much you could tolerate and so three sibs is your limit.
Cheeper by the dozen is probably your favorite movie. You are a rare breed who would thrive in a huge brood. You would would enjoy the chaos and all the chatter of a large sit down meal with the family. You would see your siblings as your built in group of friends.