Hiya Jill,
Hmmm, I would definitely say take an old shirt made out of cotton or denim, you will be surprised at how much that glass can ping about!!
Have FUN, I know that sounds obvious but it can be nerve wracking for the first time, just go with the flow, learn the basics before you leap ahead, it makes the leaping ahead later so much easier if you know the ins and outs.
Don't be afraid to play, if you want to try a clear blue bead with orange dots........do it, its your creation, no one can say its wrong but you
Have a wonderful lesson my lovely, I really hope you enjoy yourself