Quite simply, absolutely not!
The general view of people who practice yoga is that theyre all super bendy and toned, this is quite simply not true! That may, however be the majority of the images of people you see showcasing yoga, but theres a lot more to it than that.
Yoga is for all shapes, and all sizes.
You do not need to be flexible to begin with, this is something that may come in time. We also need to respect that everyone is different, and we all have different bodies and capabilities. What might be possible for one person, may not be for another, for various reasons.
One very fundamental reason, is skeletal variation. Despite what we think, not all of our skeletons are shaped the exact same. This can mean certain poses that require a very deep opening in the hip, simply might not be possible for some people.
This is why its important to note that yoga isnt about the outcome, its about appreciating the journey, and learning to love all of our own uniqueness!