DD is about to turn 12 - her party is the weekend after next. She has recently got into the Back to the Future films and wants a few friends over for a "Back to the Future" themed afternoon/early evening (bit retro I know, but that's what she wants!), the main part of which will be watching the first film. That's fine with me, I think the films are entirely appropriate for that age group.
Anyway, one of her friends is from a very strict religious family. There are many things this girl is not allowed to do, including going anywhere on Sundays. Because of this we are having the party on the Saturday, even though Sunday would actually be more convenient as DD has a sports match on Saturday too.
She sent out an invitation a couple of days ago and most have already replied saying they are looking forward to it. The girl from the religious family sent an email last night - she said that although the party sounds fun and she would like to come, her parents (and her apparently) feel that Back to the Future is not an appropriate choice of film and could we change it?
DD is upset - she wants her friend to come but has been looking forward to this for a while now. I told her to think about it and not reply just yet.
What should we do?