Yoga is 99% practice and 1% theory.
Yoga is for internal cleansing, not external exercising. Yoga means true self-knowledge.
Do your practice and all is coming.
Yoga is possible for anybody who really wants it. Yoga is universal.... But don't approach yoga with a business mind looking for worldly gain.
Lazy people can't practice Ashtanga Yoga
Anyone can practice. Young man can practice. Old man can practice. Very old man can practice. Man who is sick, he can practice. Man who doesn't have strength can practice. Except lazy people; lazy people can't practice Ashtanga yoga.