The guys are right, this is a joint wedding, and if she won’t compromise over this first joint decision, then you have a choice.
Either Marry her and be happy that she’s either going to make ALL the decisions for the rest of your life and you’re not, or sit her down and decide whether this marriage is a bad idea, until she grows up and learns a successful marriage is about compromise and not acting childish every time she needs to consider someone else’s feelings.
(Spoken from the position of having an Ex that behaved in a similar fashion)