All the previous Barbie movies prior to this one were actual movies she made and starred in.Moreover, Barbie In The Three Musketeers, and Barbie in a Mermaid Tale were all mentioned directly (the latter was seen as a poster). For this reason, all the other movies (inlcuding this one, mentioned below) likely exist in-universe as well. For this reason...
This movie is Barbie's directorial debutThis is the first Barbie movie to be credited under "Barbie Entertainment"note . Assuming that the above is in fact accuratenote , and considering the plot, this very movie we're seeing is in fact the first movie that she herself directed. It kind of makes sense