Are there bullies who are younger than their victims?

Yes there are. It's about the size of the person and not the age, and also the frenzy of a 'pack mentality' meaning a group of younger kids ganging up on a older, but smaller one. Some of society doesn't realize that bullies can range from a very early age and it's just not teens. Also adults can be bullied by their mates, coworkers or even a boss or some so-called friends.