Whenever starting a new behavior, whether new movements, new ways of thinking about things, or new ways of relating to others (all of which Aikitaiji will challenge you to do), its natural to feel uncomfortable; even anxious.
This is because your old habits, even when they're unhealthy, are known and more comfortable than the unknown.

The adventure of moving into the unknown is stressful. But an adventure is only an adventure because of the stress of anticipation, the excitement of conflict (internal psychological battles, conflicts with those who think they know you well, and even battles with nature), and the hard work of finding meaning and familiarity in the new world you are creating.

Learning itself is stressful. It implies a willingness to let go of old conventions and clear space for new content. The act of mentally "clearing space" (see empty your cup) creates something called an existential void, or an environment that does not yet have internalized meaning, and can feel anxious and even terrifying.

The way to fill the void is through practice. Practice through the discomfort, anxiety and fear until the new movements, new behaviors, and new perspectives become familiar. And through continued practice, these new things begin to take on deeper levels of meaning, becoming a part of your very being.