Your teacher has made the mistake of thinking that theme colors remain the same and keep the same names. Microsoft regularly issues new themes with different sets of colors, and the colors are named automatically. So if you're using a different version than your teacher, you may not be able to find a color named Gold in the Accent 4 location.
Your teacher is using the old Office theme that was recently superseded by a new Office theme a few months ago. Here is a sample document created with the old theme that has Gold in the Accent 4 position: Document with old Office Theme Download it to finish your assignment.