Earning your college diploma is much more than a run-of-the mill moment. Graduation marks a huge educational achievement, and it also symbolizes your transition from student life. You might feel more adult just by virtue of saying that college is behind you, but you need to show employers that you identify with the qualities of a professional.
When you're discussing the internships or jobs you held in school, talk about those positions as your professional experience, not just "work experience." You might have been a student when you held those jobs, but you need to convince the interviewer that working in the post-college world will come naturally to you. Presenting your experience in this manner is just as important as how you present yourself in a job interview.