Big fish in a small pond
Meaning: to have a lot of influence only over a small area, a person who is considered important primarily because the place or setting is small
Example: I like the idea of being a big fish in a small pond. Diane was a big fish in a small pond in her hometown, but when she moved to New York City, nobody knew who she was.
Example: I like the idea of being a big fish in a small pond. Diane was a big fish in a small pond in her hometown, but when she moved to New York City, nobody knew who she was.