Alright, I survived my first bikram yoga class.

I enjoyed it. It is definitely challenging, but you just have to do what you can do and when you can't do any more then you don't. I wore shorts, and a camisole with a t-shirt over it. I sweated buckets--everyone does. Everything I wore is soaked, and the towel I used is too.
I wouldn't worry about being fit or not fit. It's true there were a lot of hardcore fit people, but honestly, the room is so hot and what you are doing is challenging and requires concentration so no one is looking at you or caring about you. And if you don't want to wear a tank top I don't think it's a big deal... I survived wearing two layers on top as I mentioned (I often wear a camisole under a t-shirt to exercise because I have saggy skin and it jiggles around a lot which annoys me).
If you have ever done regular yoga, you know about the whole philosophy so I won't comment too much on that. If you like the spirituality of it, then you will enjoy that part... and if you'd rather just take the exercise and leave the spiritual stuff aside, you might find the ramblings of the teacher a bit irritating depending on the instructor you get. The instructor I had was pretty cool... she managed to balance that aspect while not becoming too mystical if you know what I mean.
I suggest you try it and don't wait.
