I actually belong to the last year's application cycle, but I wanted to give everyone a little sigh of relief.
For those that are wondering why they still haven't gotten interview invites yet - dont worry too much. My invite came three months after secondaries were received. I thought I might not be a primary candidate, but once I went to the interviews, they decided to admit me right there. So, dont stress if you didn't get a rapid interview invites, application cycle has only started.
Also, for those who really want to go to UMich, stay confident! UMich is known to have a very high wait-list turnover rate. Apparently UMich accepts a lot of applicants early in the cycle, hence the rapid interview invites, but a lot of accepted applicants decline their offers later in the cycle, resulting in almost half or more of class coming from waitlists.
I can't be sure this year would be same, but this was the story from last year's cycle.
UMich is a great school, and I liked Ann Arbor. Best luck to everyone, and
hang in there, it's a tough few months ahead, but before you know it, you will be there!
CY.