Don't worry at all!
Expect to stay in the room for the full 90 minutes and for it to be very warm.
Bring your mat, a large towel to go on top and I like to bring a small towel to blot sweat from my face now and then and a small bottle of water.
You can take little sips now and then and many teachers actually will tell you when it's a good time for that. Just enough to moisten your mouth, not to rehydrate you.
Sit in the second or third row and make sure you are staggered so you can see yourself in the mirror to help check your form and to focus on yourself to help balance during the standing poses (asanas). You can watch the more advanced students to help get you to the correct place.
Don't be afraid to lay down and rest if you need to and remember that it is your class and no one else in the room really cares how far you reach or wobble or if you finish at all. Camel in class makes me want to barf, every single time... so I sit out camel in childs pose and I try to do camel at home. No one has ever cared in any of the studios I've taken class in.
If you have any medical stuff like knees/hips/joints whatever, let the teacher know and they will suggest modifications so you don't get hurt.
Your spiritual path may not be the same as the teacher's, be open minded and let anything that doesn't mesh with you wash away.
Have fun! You should leave the class feeling like you've really accomplished something!
Last edited by Spinach; 05-21-2012 at 06:19 PM.