I signed up for my first yoga class (power yoga). What should I expect? I bought a yoga mat- anything else I should bring to class with me? Will my complete lack of flexibility make me the laughingstock of the class? Inquiring minds want to know!

yay yoga class!! good for you!
as far as what to expect, it's hard to say, since each class is so different. Even at the same studio, different teachers might be very different. Power yoga is often more strenuous and will have you moving a lot, as opposed to kripalu that is more just stretchy. Is your class in a heated studio?
please don't worry about others in the class!! No one will laugh at you! Yoga is not just physical exercise, it's also a spiritual exercise. People who practice it should also be practicing mindfulness, caring for the spirit, etc. These values don't translate into humiliating others! Any yoga instructor knows that, and should create a class environment that is gentle and caring.
On that note, the one piece of advice I would give is to introduce yourself to the instructor and let him/her know it's your first class. You'll get more attention that way, and the instructor should offer modifications for more difficult poses. And always remember, if you get tired, go into child's pose. There's no shame in it.
Have fun!!

I love yoga. Power yoga has more moving, but is a great class. I would reccomend clothing wise wearing a tight semi-long shirt if you dont want your belly showing. You will be doing inverted poses and a big loose shirt will just fall up in your face. Also pants that fit in the waist and are not too big cause its a pain to have to keep fixing them in your poses. Also if a pose if too hard the instructor should show a modified pose. Dont be afraid to ask for a modified pose if one is too hard. If you need a break child pose is great. Also dont pay attention to the other ladies because some may have been doing yoga for years and some just starting like you. Concentrate on the pose, breathing and getting away from your daily stresses. Good luck and have fun

I'd say bring a towel and some water, I tend to sweat a lot when I do power yoga. Like candygirl said, if a pose is too hard, ask for a modified one if they don't show you. Everyone started off somewhere with yoga, I don't think anyone can do a peacock feather the first time they try it (take a look, it's a crazy pose). Just remember to relax and enjoy yourself, yoga is all about the experience. Forget about all the junk you did before and everything you have to do after, live in the moment and it'll be an awesome ride.

Bring a towel and bring plenty of water. Oh....and quiet your mind. It really helps.

Don't eat for at least two hours before class. Have fun, ask questions, and as has already been said - ask for modifications! If they have a shelf with blocks (bricks) and blankets and belts - these are called props - grab them when you enter. Follow the lead of others in the class - and most importantly - HAVE FUN! You will LOVE it!
(sorry for crashing the thread (I'm a 50 something) but I loved the topic and my DIL is a yoga instructor)