I would try to schedule interviews with the schools on the bottom of your list towards the front, that way you can get some experience and hopefully get some nerves out of the way, that way when you get interviewed at the school towards the top of your list, hopefully you'll be more prepared to execute a successful interview. Thats my opinion and Ive heard that from many in ds.
I would take the early dates as most schools have rolling admissions. Also if you can set up a mock interview with dental questions from your undergrad this could help take the edge off. It all helps that way your first interview is a little more polished. Another thing that pops up is if you get more interviews and need to reschedule to a later date you have built in some buffer space. Also if your in undergrad really look at any lab dates as I ran into conflicts.