The award is for her efforts in this past BVB season, as she and Schafer went 20-8 overall as a pair. Seems like beach and indoor have different criteria for the AA honor, yet there are many reasons to be proud of her. I'm quite certain that if Cal VB makes the NCAA tournament and does well, she will have All-America honors in both indoor and beach, something that no Cal bear has ever done. It's pretty clear that she is the greatest Cal volleyball player of this generation.
https://calbears.com/news/2021/5/12/beach-volleyball-mirkovic-named-avca-second-team-all-american.aspx
https://calbears.com/news/2021/5/12/beach-volleyball-mirkovic-named-avca-second-team-all-american.aspx