What can happen to me if I'm 17 and I got in a fight on school grounds?

I am assuming that for the initial assault and theft you are still in probation? One of the provisions in your sentencing was no further law violations. Not knowing the circumstances of the fight, one cannot give specifics. If you started the fight, you will be expelled from school as a minimum. The potential assault charge will impact you directly if you are in a Stimulated Order of Continuance (SOC) or a deferred sentence. You have completed the diversion program for the assault, so they likely cannot renew the assault charge. Here again, it depends upon the terms you entered into. I would talk to a criminal defense attorney about the specifics of your case. There may be mitigating factors. Good luck.