P90X Day One - Core Synergistics

Wow. So, I started my Power 90 X journey today. I decided to go with the "Lean" version of the program because I still have some more fat I want to burn before bulking up in any way. I'm sure I'll be doing more than one round of this baby.
Day one in the Lean Program = Core Synergistics
Oh my gosh that workout is intense!!! I couldn't do all of the moves all the way through. I did, however, do pretty well, I think. I was still learning today, so things were a little slower going for me. I was proud of the fact that I didn't need to be on my knees for any push-up moves (not that you can really do that with any of those anyway). The prison cell push-ups are intense! Wow! I didn't do too terribly shabby with those, though. Woo! I think I'll be pretty good on this one by the end (heck, I'd better be!).
The only moves that really gave me trouble were the banana rolls. My back is arched when I try to get into the banana position... so that's not too good. It's probably because I'm not strong enough in my core yet, but I also think that my bubble butt may be playing a role in that too. It also hurt my hip to roll over it so many times. I have large hips, so the hipbone is rather prominent. I don't think my back was totally straight when in boat position either.
But hey... this means I'm open for a lot of improvement. It supposed to be challenging, yes? If it wasn't challenging then I'd have to be already in pretty rockin' shape (and I'm not bad... but I'm not quite X worthy yet).
Cheers!