How well do you know the couple? If they are strangers I would be reluctant. Two reasons:
1) it is a wedding. Brides and their mothers tend to be VERY demanding AND particular. IF you are new to this, it is alot of pressure. You may want to cut your teeth on a few grad/reunion parties first!
2) In Ohio, if you are charging a "per plate" fee ,then you ARE governed by the HD even if it is a private party. They prolly wouldn't catch you, but you would be illegal just the same.
"I was born to cook for people"