TDA Misunderstanding

I think I might have screwed up.

I went in to Truck Driving Acadamy in Sacramento, for Central Refrigerated Services, last friday and signed up. On the application it asked if I have had any convictions. I put down no cause i think it said in the last ten years, but now, thinking back, im not sure. After reading on these forums (like i should have done in the first place) that it should be ANY convictions, even over ten years, then I think i probably told a lie. I keep wracking my brain trying to remember if it actually said that on the convictions part or if it was on the employment history part, or both...

Anyway, Im thinking of calling Central tomorrow and speak to either human resources or recruiting and telling them that i might have mis-understood. Ive re-read the contract I signed and it says that within the first 5 business days I can quit the contract at no cost, which I might have to do, because I fear that if I did make a mistake they will think im lying and I will end up owing the tuition if they fire me. But my thinking is that i'd rather be rejected for telling the truth than be rejected for telling a lie.

What should I do, and what possible outcomes should I expect if I did mistakenly lie?