Think it'll have to be a big fat no to be honest, that's an approx cost as well, then she'll need spends. Believe it or not, every year this trip is over subscribed and they draw out of a hat.
Well at 12/13 it's unlikely she'll be able to fund it herself.
As above, why Colorado?! Tell the school there are plenty of dry ski slopes here in the UK!!
Our school was the same RR, we had ski trips all over the place, although it was cheaper back then!
I'm sure she will understand if you say no, especially since you are hoping to go to South Africa :)