you'll be ok, listen to what the instructor has to say and you'll be fine.
Take your time once you get on the road, ride out on your own for a while so you dont have any peer pressure to ride faster than you feel safe doing.
One thing I would recomend is practicing emergency stops a few times, dont just grab a handfull of front brake, squeaze the lever progressively until the brake's on full. Good practice to know how much distance it requires to stop.
You may here many tales of cars pulling out in front of bikes, and yes it happens. I have a good tip for trying to prevent this hapening so often.
Try to position yourself so you can see the drivers eyes when he/she looks your way (allways cover the front brake and be prepared to stop) if you cant see the drivers eyes then move away or toward the curb to give him/her a clear view of yourself.(many blind spots in a car)
Welcome to the most expensive hobby you'll probably ever have.
And enjoy it.