Chickening out

so there it is, no nice way to cover it up: I am a chicken!!!!
Not the feathery kind but the scared one without a backbone when it comes to it......
This is how this inside hit me:
Today's class was taught by Carla (the just certified Bikram Teacher). Since, for a couple of days, we do have 2 new faces at the reception desk ( Leah & Kimberley (hope I spelled their names right)) I went up to the desk to introduce myself. That's when Carla got me, asking how I felt about delivering the Half Moon Pose in front of the class in 15 Min. ? I stood there frozen in place, my mind running through all the reasons why that definitely didn't seem to be a bright idea, and some, very sparse, reasons why I should go for it. Needless to say that I declined.
It got me mentally totally unprepared.
Now, I've been asking Anastasia if I could practice the Half Moon Pose one time before leaving, but that hasn't worked out for various reasons, so I kinda gave up on it. That might be one of the reasons why I was caught off guard by Carla's offer??
Once in the hot room, on my mat warming up, I could have hit myself for not having any backbone and passing this chance!! I was reciting the dialogue in my mind and didn't have a problem, so I should have been fine, but the opportunity was gone.
It is kind of frustrating to discover this particular  trait in myself, I have to admit!!! Humiliating even? I guess that that is only in my eyes!  Definitely frustrating, that's for sure!! I will go into my corner and mull it over and hopefully be able to accept a gift given to me, unexpected, the next time it happens....... grovel....grovel...