OK, Just my opinion but if it were me I would not let a family member, even Mom wreck my idea of what I want for my wedding. I have had family give their opinions and then expect me to do what they say, to me that is wrong. It is YOUR choice with your guy, don't let other people make you feel bad for doing it your way. I would explain to Mom that you would like her to be there but understand if she does not come. Disney is for kids of ALL ages anyway! I hope it all gets worked out and your day is perfect!