Her behavior and her ask is abusive, and it will not get better, but worse over time, and it will eventually involve your kids if you have them. You don't want to be married to this toxic person.
Ok you're a little nuts, pp. Couples elope all the time, especially now. She doesn't want to wait any longer. Perfectly reasonable. OP if your family's feelings always trump your future wife's feelings, your not in a good place to start a life together.
When it's safe to do so, suggest a small cocktail party that your family hosts and pays for, much like a rehearsal dinner.