KAJohnson congrats on your interview! I came across a blog that had an interview with the assistant program director. This was published in Feb last year but I think it hasn't changed. She said that they did not do rolling admissions and only offered early admission to some stand-out candidates. Looking at the thread last year this sounds about right.
There's some other great info about the program. Here's the link if you want to check it out! https://beaphysicianassistant.com/blog/samuel-merritt-university-pa-program-profile