One of our local instructors has students do nothing but listen to music for a few minutes, to become familiar with the rhythm and to learn to recognize the "1" beat (downbeat). If you can get your instructor to do this exercise with you, it may help.
Sometimes if you really have trouble you can try clapping to the music. Do it where you don't feel stupid and don't freak out. Sometimes you can get confused because more than one instrument will play at a different timing which can freak you out. Also know that a lot of people can make a song work to more than one timing and so if you see them dancing to something that doesn't make sense to you don't freak out. Timing can be a little bit subjective and no one tells you that in the beginning which really can make it hard on someone new. Close your eyes and listen to the strongest beat that underlines the music. Try to listen for the drums or whatever rhythm instrument is strongest.
If that fails close your eyes and let your body move to the music. If you've danced long enough you will naturally and without thinking go into proper movement. Then you'll be able to cut out the cognitive fear that you are going to make the worng choice :~}