Although there are different schools of thought regarding what is considered beginner and advanced, for some teachers there is no distinction between the two because everyone should be able to practise yoga at any given level and every different type, because there are no levels in yoga.
However, AwakeConBal philosophy is based on extensive social observation and my own personal journey, which reason that if Yoga principles teaches us that the human being is made of multidimensional koshas (layers), therefore to awaken, balance and work on each layer/kosha it will require a deeper level of Yoga application each time. These deeper levels of application is reached through unlocking deeper mental awareness to allow for deeper connection to each kosha/layer in turn.
It is not so much a distinction in how flexible or well is ones yoga practise but rather if each subsequent kosha/layer has been awakened, unblocked and worked on/addressed properly through ones daily practise of yoga.
I had noticed during some of the yoga classes I had attended, many individuals whom I would term beginners yet they were practising advanced yoga forms, I observed that they were struggling and after two classes did not return. There are some serious risks in beginners practising and attending advanced yoga classes and one of the main risk, which would induce anxiety, is the awakening of the emotional body before the mental body is ready to confront it.
The practise of yoga will unblock trapped emotions and subconscious issues that might had been suppressed by the mental body for its own preservation, by unlocking issues before the mental body is ready to address them might create more damage then good. A beginner must start with gentle self-awakening yoga to introduce themselves to the benefits and wonders of yoga practise and to gradually come to terms with the internal awakening process of self-discovery, which yoga delivers beautifully with patience and time.
If you are experiencing anxiety when you practise yoga but you have been a practitioner for a while, then it could be that there is a deep-rooted issue that your mental body is rejecting to address but is surfacing nonetheless. Again calm your senses, assure your mind that you are ready to confront the issue, if you are indeed ready to see behind the veil, and then go back to gentle yoga to experience the issue from a gentle calming place.
Whenever one of your multidimensional layers create an emotional challenge, remember that it surfaces so we may witness its reality, understand how and why it is present within us, heal it and then let it go. By staying true to this process we push our evolution forward, becoming better human beings as a result and more aware.