i love the idea and you know the girls better than us as to if they will like it. i think some teenages would love it and some would hate it/not get it
My mum always does a KIVA donation for every occasion - even for my littlies (2 and 4 yo). they get a present too but i explain we are helping others who have way less than us too. they love choosing who to donate to - and we then look at pics of the country they are from etc (much younger kids but i love to instil charity from young age)