These are all parts of those important first impressions which really can earn you points. You are alone. She is a valuable person to know. Dress the part. When you walk in the door of your internship site, even if it is on campus, you are no longer a student.
Appropriate attire is different for every organization.
Look around you. Model your dress and grooming after that of your supervisor and other professional staff, and you cannot go wrong. Lose the lingo. In your internship, it will tell people that you are not yet professional material. Listen to the language of those around you, listen to your own language, and speak as a professional.