You should still attend the fair! Go to learn more about what jobs available and what employers are looking for in candidates. Use it as a networking opportunity for when you are actually looking for a job. You still need to do your research and be prepared. The difference is that your job is to gather career information, not get a job. Eavesdrop on the conversation between employers and students. Get an idea of how those conversations work. Another option is to volunteer to help with the fair.