Yoga is an ancient Indian practiced designed to promote relaxation, health and flexibility. Yoga is not a recent practice.
Unlike traditional weight building exercises, in yoga your body provides the resistance. When it comes to aging well, yoga is one of the best activities you can do. Also, make eye contact with individual students throughout the class to show your openness and confidence.
An important point to realize about yoga for a beginner is that it is non-competitive. Yoga can be beneficial during pregnancy for example, and there are many women who suffer from circulatory problems during pregnancy. With yoga, you can benefit from relaxed breathing with a reasonable degree of control.
Kundalini Yoga is extremely spiritual and tends to focus predominantly on breathing exercises, chanting, relaxation and meditation. No one expects you to transform overnight, so keep at it.