had something slightly simular recently, myself and my husband booked for vegas then discovered this visa thing, my husband had a drink driving conviction from when he was 19 (he's now 48) also we were arrested for drunk & disorderly and charged but aquitted this too happened many moons ago. So I phoned the american embassy and was told by the advisor we would need to apply for visa, (but my understanding was that they have to tell everyone that as the decision is not theirs) we were told there is no such thing as 'spent' convictions, so before we booked our appoinment we had to get a police certificate which would detail everything ever on file about us, luckily when it came back it said 'no trace' of criminal record found, so that's it we shan't be bothering either, but if you feel happier getting one of these certificates see your local police station these can be done within hours, it might not show & give you peace of mind. Hope everything goes well sure it will, enjoy yourself.