Is it bad not to have references?

Yes, it's bad not to have any references. Remember that most listings on the job market are somewhat too highly competitive. Therefore, if your application lacks references, while three other applicants have them, your resume might not be viewed by an employer.

Remember that it's not that you don't have references, just that you can't think of any right now. Odds are you've had at least one teacher who would recommend you or a friend you've done some kind of project with.

Don't worry about how "professional" your reference is if you don't have much job experience. Instead, find someone who will be able to paint our character, skills, and qualifications in the most positive light.