I am sorry just remember it is the religion they belong to that makes them feel this way, without that influence you could all share her happy day and rejoice together. how dreadful that they and you are put through this pain because someone has decided that if you choose to live your life differently you are not welcome.
Do what you can to show her you are proud of her and thinking of her who knows in the future that may mean more than you know. Time is with you there was no rature today and no big A so who knows what the future will bring.