I'm sorry that she seems to have had a change of heart Pens. I've been to lots of weddings where 0 kiddos were allowed and I know it's never an easy decision to make as a parent as to how to handle it.
Maybe if you're able, attend the ceremony IF someone you trust could watch LO and pass on the reception? Maybe even a friend could come along and watch her in the nursery at the church if they're having a church wedding, or something like that? Then you wouldn't be far apart but you could still go. Just a thought.
Otherwise, no shame in not going if you're not comfortable doing so.