The Bi-Co class does not discriminate on the basis of gender, race, ethnicity, sexual orientation, number of left feet, or any other nasty criteria. But as a nod to the historical origins of Scottish Country Dancing, it is requested that women wear skirts or dresses to class. Men who own kilts are welcome to wear them, but they are not required for dancing.
Ballet slippers are perfectly appropriate shoes for a beginning dancer.
As you progress, you will probably want to invest in a pair of ghillies. These dancing shoes provide extra support and will help you with your technique. Balls are formal social events. Men should wear kilts, or slacks and a dress shirt. Buying trips are often organized for these items as well.