Exercise your body before attempting that, if you're unable to do a bridge, I wouldn't suggest you doing that because it will only result in hurting yourself.
First practice doing a bridge by itself, when you feel your body can take on that flexing, go for it.
You need to be able to 1. hold a bridge comfortably (not just force it) and 2. have sufficient strength in your abdomen (the same strength required to do a backbend, I guess). I've hurt myself doing it when I wasn't flexible or strong enough, lol. So believe me, BE PATIENT or you're gonna end up embarassed and in some serious pain. XD
yeah it's easyer than a backbend in my opinion.
Maybe, it just depends on how flexible your back is, i can but thats probably only cause i used to practice ALL THE TIME when i was in gymnastics.