Every interview is a an opportunity.
The main reason why you should accept an invite to any (and every) college interview is that each invitation is an opportunity to get admitted for tertiary study.
You are part of the lucky bunch.
You should treat each interview invitation seriously and not pass up any chances - some students don't even get asked to attend an interview.
Consider yourself fortunate to have cleared earlier filtering by the school to have reached the stage where you are now.
Plan for the worst and have a contingency just in case.
Plus, you never know if the dream college you want will want you as a student. It is thus important to attend interviews at other schools and try to get a placement there as they are your backup choices.
Have some second-tier schools as an alternative in case you fail to get into the school you want - so at least you get into college at the very least.
Then if you really, really want to attend your first-choice college, you can seek a transfer when you are enrolled.
Use the "non-important" interviews as a practice rehearsal.
At least use the interviews you don't really want to go for as practice.
College interviews are a great way to show the college that you're interested in attending, and demonstrate your enthusiasm for their institution.
During the interview, learn more about the school and get all of your questions answered (without fear of harming your application) by someone who knows it inside-out.
Some of the points discussed during the interview can be reused for your subsequent interviews.
The experience will build confidence throughout both applying process as well.