Hi Petalleaf,
This is a wonderful piece. The tone is full of anxiety. It grabs all the reader's attention and makes them want to read on. The reader is wondering what will happen on Stella's first day at her new school. They will read to the last word to find out. The plot is straight forward and moves along logically. The story is abut a teenage girl who prepared to face her first day at a new school. The conflict is well defined. There is no doubt about what is going on here. The characterization is fully developed and believable. The story concentrates on Stella, and she comes across as a real person. There is only one line of dialogue, and it is well done and realistic. Stella speaks like a real person. The description is detailed and vivid. It puts the reader all the way into the story. I did come across one structural issue that needs your attention:

1)I walked through the doors of my new high school and the-There should be a comma after "school".

The story is consistent in terms of point of view and tense. You have accomplished a great deal in just a few words. Great job.