How do i know if i have a Criminal record?

So I want to join the USMC & I plan on going to see a recruiter in about a month. Now I just need to know what to tell him if he asks if I have a criminal record. While in HS at age I think 17 or 18 I got into a fight with some kid. I remember being held at a Prescient for awhile. I also remember them taking pictures of me & fingerprints. I seen a judge & the case was dismissed so I never did anytime or anything like tht. It escapes me wat the actual charge was. I Just got suspended from school for a few months. So do I have a Criminal record now? Do I mention this to my recruiter ? How I can I check to be 100% sure to know if I have a record or not? Because I don't want to be seen as withholding information from him.