Having just been through the process, I'll chime in. My understanding from last year, was they did a round of interviews (both in-state and out-of-state) in October for people who submitted vmcas before Sept. 1. My round of interviews were the first week in December, and Hilda seemed to indicate that everyone has submitted before Sept. 15. Then, the bulk of interviews were held in Feb. How many seats were left when I got in, in Dec. I have no idea.
Hilda is very nice (as is everyone in admissions at MSU). If you have questions for them, like Jenn said, contact them. They know it best.
To answer your original question, no I don't think it's too late at all. I would, however submit as soon as your ready, and as soon as possible.