If not now, when?

Anyone who practices can obtain success in yoga but not one who is lazy.  Constant practice alone is the secret of success.  

(Hatha Yoga Pradipika)

Yoga is 99% practice and 1% theory. 

(Sri Krishna Pattabhi Jois)

Before you've practiced, the theory is useless.  After you've practiced, the theory is obvious. 

(David Williams)