Andy,
greetings.
Well what to tell you before you even begin? It is an interesting question. Obviously you will be “introduced” to Yoga at the studio. You’ve made a mindful choice regarding a studio and while all Iyengar teachers and studios are not created equal, it is a safe stone in which to start the path.
The capital Y yoga which is very vast, as opposed to the little y yoga which to many is exercises or “stretching”, is much like schooling. You will get out of it what you put into it. You will take what you bring. And at the same time there is a dichotomy. You will get more when you bring less. And that bringing less means expectations. If you are able to walk in there with an open mind, an open heart, and an open body you will reap a grand harvest.
Many are not able to go in with these three openings. In fact some go to Yoga because these three openings are NOT open. This is fine. But do consider the concept of “how am I walking in here”, “what is the nature of my mind”, “what is the nature of my breath” and “what is the nature of my body”. In this way you will feel Yoga rather than just do yoga.