Yes I have been practicing for many years. Poses are just part of a practice, but yes some of them can be a physical challenge. However, if you take a mental posture that you LOVE challenges, you might master them very easily and quickly. If you take the mental postures that you HATE challenges, you will likely struggle and not enjoy it and maybe even give it up soon!

And it's also interesting to start a practice and find that some poses are very natural for you, while others might require more effort. Then if it interests you, you may find that the poses that challenge you are also good for certain parts of the soul...like, let's just say maybe you are challenged by a class of poses called heart openers, you might start looking at your life and find that you actually hold a lot of grudges! Maybe you start meditating on that and looking at that, and as you learn how to forgive, the poses actually become a lot easier.

That's just one example - yoga can go very deep!