Tomboy Wears dress everyone gets set to laugh

Soooo I'm not sure I'm a tomboy really just depends on your definition. I'm a real jeans and tshirt kind of girl. I would get married in pants if my FH weren't so adamant about me wearing a dress. I get it and I have a dress that I'm happy with. I really liked it when I put it on. It was comfortable and flattering. Here's the issue. Like I said I don't generally wear dresses and terrified of tripping and falling or doing something else to make a complete ass out of myself. Advice?