Backbends are one of the toughest poses in ashtanga yoga. Correction, doing backbends properly is really tough, at least for one yogi who does not have a very flexible back.
I finally learned to go back into backbends from standing while in India, but coming up was a whole another challenge. I have basically spent almost every practice since then working on coming up. And today I did it! I am keeping my fingers crossed that I can do it again tomorrow, and the day after and the day after...you get the idea.
Yoga definitely requires much patience and dedication. But I really believe good things happen when you do your daily practice.