Am I overreacting?

My dad takes me to school in the mornings, on Fridays I have late start meaning it starts an hour after. Yesterday I had told him to pick me up at 8:20, he texts me and says he had arrived at 8:08. I told him that I will be down at 8:20 considering that is the designated time I set. I get outside at exactly 8:20 and he is gone. He left me. AIO?