To learn yoga consider learning it with others. Get a group of friends together to learn yoga together and make it something you do together to reduce fears and to make it more enjoyable in the process. Chances are good that you will find yourself improving as you go.
When you want to learn yoga or anything new to you, consider the various options that you have for your physical body. Do you have any limits and if so, can you do yoga around these limitations? If so, chances are good that you can find the right yoga facility for you.