From my experience, college interviewers treat students like adults, i.e..they have a personal choice yadda yadda. Sometimes it can be surprising for a teen who's always been around bossy parents and teachers.
Not saying that your piercings won't make an impression but what's most important is what's in your head. Everyone has their own style, and colleges know that. What matters is that you represent yourself well, speak with confidence etc. You can still impress a college interviewer with your merits!

all the best. Say, you have piercings and say, you have some interviews. So come back and tell us how they went
