If you don't know what to start with, perhaps try something you're interested in or knowledgeable about. For example if you're a history student consider a historical fiction piece about a setting you've studied in history, so that you can be convincing. If you're a migrant or 2nd generation migrant, you can write about the language barrier between you and your parents/grandparents, etc. Find something that might be interesting from your own knowledge base, or research something you think would be cool.
If you're still stuck, try looking at books and movies that you enjoyed and adapting parts of them to make your own short story. Don't be afraid to copy, as long as it's not straight up plagiarism.