What should I wear to court?

Just to clarify, I'm not in any trouble or anything like that. I'm doing a residential course for my gold Duke of Edinburgh award at a police station with some other people my age (I'm in my late teens). I just got the kit list, and it says that I need smart clothes for court, because apparently we're going to court on one of the days. The problem is I don't really own any smart clothes. What should I wear? Should I just wear a simple black dress with plain shoes or should I wear a suit? I'm really not very experienced with court, so can someone help me out here? Also, do you think they'd be okay with me wearing a skirt suit if I'm not allowed to wear a dress? It's just because I have very short hair at the moment and I don't want people to think that I'm a boy. That and I'm not really a huge fan of trouser suits for women. Thanks