Do I need to have a yoga mat or other yoga props? A yoga mat would be helpful, but it's not impossible without one. Bricks or blocks, cushions can be good if you have any. A blanket is nice for relaxation at the end of the class. I have various props and yoga mats for sale at internet prices, if you're interested.
What should I wear? Comfortable clothing that allows you to move and that you feel comfortable in. That can mean loose-fitting clothes or clothes that are closer-fitting, whatever you prefer. You get more out of the yoga with clothing that you feel good in. Jeans are not appropriate as they do not allow for enough freedom of movement.
Do I need to be flexible in order to benefit from the class? Not at all. As a matter of fact the less flexible you are the more you might benefit from a yoga class! The classes are not about being flexible, but rather about working with where each individual is at.
I have a medical condition or am post-injury. Are the classes still suitable for me? Most likely but please contact Maria beforehand to check. Modifications of postures are very often possible and yoga can be extremely beneficial for many health conditions!