Almost not sending her to school

Again, despite my several attempts to warn my girl to be faster if not I will not send her to school, it still never get into her. The clock show's almost 7:30am and still she is not ready to leave. I got so PISSED OFF. I shut the car engine and close the garage door and say, I am not sending you to school already. I get so FED UP always having to wait for her while she take her own sweet time. I have to end up rushing for time. After 7:30am, the road got more cars and traffic gets heavier. Told her so many time not to squeeze my time coz it can coz me to rush and get into accident but guess she doesn't care. Argggghhhhh..... GOD please show me how else can I do this?