I think interviewing is a great idea if you are interested in the school. It’s a good chance to show a different side of yourself and to talk to people that actually go or have gone there! I actually haven’t done an alumni interview with William and Mary, but the ones I have gone to have been pretty chill.
These links are mostly about on-campus interviews, but from what I can tell from talking to people who have done interviews in the past, it is really casual and William and Mary students often like to put a creative spin on things. It’s not supposed to be stressful at all.
http://talk.collegeconfidential.com/college-william-mary/1664109-what-to-expect-for-the-interview.html
http://talk.collegeconfidential.com/college-admissions/964526-on-campus-interviews-for-william-and-mary.html