I’m confused: Are you a junior or a senior? I think you have a very good chance of being admitted, but USC is very competitive. If you want to go there, you should tell USC that. I would submit all your scores, which show your scores are not a fluke. You did well on all of them. USC does not require subject tests, but your scores are over 750, so I would send them. It can’t hurt. Also, USC superscores the SAT, but not the ACT. If you are a junior, try to show an upward trend in grades for this semester and next year.