Star rating is irrelevant in the ranking process. Certain patterns will increase star rating more than others, and how SR is calculated changes all the time.
I checked out your map and the reason the SR is 2.7* is because there is large spacing in parts like 03:04:293 (4,1,2,3,4,5,1,2,3,1) -. Other difficulty elements like multi-repeat sliders don't increase star rating as much, which is why maps that are higher SR usually have larger spacing as well.
You'll also observe higher SR on faster maps (high bpm 1/2) compared to slower ones (low bpm 1/2).
As WitherMite suggested, it's more important that your difficulty is mapped like a Normal relative to the Ranking Criteria, your spread, and the song itself, in order to be considered a Normal.
Good luck with your future maps!