A specific degree, no, I don't think you need one. I don' know much about agents for models, but I do know something about agents for athletes. In terms of classes take some courses in business, specifically sports finance if that's available. The most important skills you'll need are the ability to think critically, to analyze situations and facts, and communicate effectively verbally and in writing. It's not an urban legend that many of the most successful sports agents started at the bottom -- in the mailroom of an agency or as the assistant to an agent. The big agencies -- CAA and WME -- offer internships. They are very competitive, but it's a great way to get in the door. Good luck.
This professional recommends the following next steps:
- Do some research into the agencies that represent athletes. If you have a sport you particularly enjoy, focus on agents who represent those players. If those firms offer internships, you should apply. If not, I'd reach out to the agent(s) anyway and see if you could do an informal internship.