The topic of yoga actually being stressful for some students is very pertinent. It's no wonder why. Our culture portrays yoga as either this sort of blissed out "one-up" state of being, or an over the top granola eating airhead wearing designer yoga clothing and spending a fortune getting high on the fruits of yoga. Truthfully over the years I've witnessed many students actually getting very stressed out during a yoga class. Granted that a percentage of students have a relatively easy time with poses and their level of flexibility is natural. For others coming to a yoga class or practicing yoga is daunting and intimidating. I've had many students over the years share with me that they find yoga to be frustrating and unpleasant.
As a teacher who really cares about their students progress and wants them to benefit and love yoga I'm very sensitive to all of the variations that arise. The longer I teach the more I realize that in a class of 20 students there are 20 distinct experiences going on and each student is entitled to their own. I am just a guide and the students are teaching themselves.
If yoga feels stressful to you there might be a good reason. Are you always rushing around and doing too much? Then expecting to come to yoga and instantly relax into your yoga personality? What are your expectations? Try attending class with an open mind knowing that you might not love every moment of it and that's ok. You might feel weak or strong, happy or sad, steady or shaky. Yoga is emotional, physical and mental. It takes practice to blend those elements to find the center. Practice shedding the right way or wrong way thinking. Focus more on whatever is occurring moment by moment with acceptance, and it might be a more holistic experience. When you sit down on your mat create a mantra that fits you. Keep it real to your nature and have fun with it. An example might be: "Right now I'm here practicing yoga and I can suspend all forms of judgement."