My friends birthday party is semi-formal/formal...more detail inside..?

My friends sweet 16 is semi-formal/formal which means she want's the girls to wear dresses. I don't own a dress or even a skirt. Also my dad won't buy me a dress and I'm not comfortable wearing other peoples clothes. I do own a pair of black dress pants and a frilly white top would I look out of place wearing this while all the other girls wear dresses. Should I just not go and save myself the embarrassment of being the only girl not wearing a dress?