I have been accused of copying two lab reports from the previous year even though I had done everything by myself Today I got accused by my professor of cheating and copying two reports I submitted. I had a formal meeting with the professor where he tried to push me into admitting I cheated by showing me the surprising similarities. Even though I continuously denied it, he went forward to go to a formal hearing in the university where a panel will judge the outcome. I am currently freaking out. I know I did not cheat from anybody and I feel like the similarity could be due to a similar thought process (which sounds ridiculous). Should I just say that I did not cheat and stick with it? Or should I ask if I can redo the reports (though it sounds suspicious)? The reports were 68 percent similar and I feel like the odds are against me even though I did not do anything. 

Edit: the software used was turnitin and I do not hav access to the original files to get time stamps. I literally can only deny the allegations. The only reasonable explanation is that the professor taught us in a similar manner and our report writing manner was similar due to the fact we have taken the same courses a year apart and had the same professors who molded our report writing skills.
In this kind of hearing, evidence will be paramount. "I know I did not cheat" isn't sufficient - that's just a denial. You need more, e.g.:


Can you show that you could not possibly have known about these 2 reports?
Do you have drafts of the report, preferably with time stamps, as you were writing it?
Did you work with anyone else? If so, can they vouch for you?


Offering to redo the reports won't work unfortunately - at this point, it's about academic integrity, not about the grade you get. It's likely advisable to get advice from someone familiar with your department and the academic integrity process, e.g. a faculty member you trust, or student counselors if available. 

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