You're nervous and excited. You've reviewed your resume and studied all there is to know about every type of question you could get. Now all you have to do is deliver the right answers. You're so close. Listen with your eyes as well as your ears.
People communicate non-verbally, using their body language.
You can actually practice and demonstrate active listening during your interview. Let the question sink in and give yourself time to answer. Your thoughtfulness will impress the interviewer, not your speed. If you aren't certain what they mean, clarify by summarizing what you think they said and asking if that's what they intended. You asked about my summer employment.