People will probably catch a glimpse of blue shoe here and there but if that doesnt worry you, then wear them.
Is your mother wearing the shoes? No, so she shouldnt have to make an issue over it. And what a silly, silly, non important thing to be arguing over. At the end of the day, WHO CARES what a bride wears on her feet. She could wear desert boots for all anyone would care.
Just get the blue shoes, stick them in your cupboard and forget about them already.