Please do not feel bad. Teenagers can be hard headed (don't mind me singing my favorite tune
THAT GOES SOMETHING LIKE THIS!!
"MY KIDS ARE GROWN, MY KIDS ARE GROWN NANNIE NANNIE BOO BOO MY KIDS ARE GROWN!!!!!!!!!!!"
I'm very sorry about hearing that she got injured but an accident is an accident. She'll never do it again and will probably warn others from doing the same thing.
I had a party a few years ago and made up a sign saying "Please do not feed your fingers to my birds, they are on a very special diet!!"