I thought of a few more things about yoga. Don't worry about how well you do in class, or if others are "doing better" than you. Yoga is a non-competitive activity. A good teacher askes before class what medical conditions people have, so she can tailor the poses to suit you best. While others in the class might be doing a pose one way, the teacher will give you additional props, or modify the pose, or substitute a different pose for you, depending on what your body is telling you. For example, if you are menstruating, the teacher will not have you do inversions, but different types of poses that massage and relax the abdominal area.
A yoga class will contain many different types of people: young, middle-aged, old, thin, fat, flexible, people with metal pins in their ankles, people in form-fitting spandex, and people (like me) in baggy t-shirts. We are all in the same class, all doing a pose in the best way our bodies let us. Yoga Journal magazine had an article once on yoga classes for people who are confined to wheel chairs and have MS. And yes, these people, some who could only move their hands, still got much benefit out of yoga. The poses were tailored to what their bodies could do, and over time, they gained strength and flexiblity in their hands and arms. Give yoga a try; you might not find the right style, or class, or teacher at first, but keep at it. It's really worth it!