A gift is a gift.

She is free to do as she likes with it. I understand your frustration though if you thought it would be a bonus now your circumstances changed. Think of it now that whilst maybe not super necessary you have helped those kids have an opportunity they never would have before.

I also find it strange though she would have told you she was giving it back and then changing her mind...but I forget not everyone says what they mean or sticks to their word.