Girls do not like to wait.
They also do not like to be rushed. I realize this is a double standard, but you might as well get used to it now.
If she says be there at (insert time here), then be 5 minutes early. If she isn’t ready, deal with it.
Remember, she is trying to look her best FOR YOU. Rushing here will only result in the “Fine! I just won’t go” fight.
Invest in a game for your cell phone. You will need it.