The page you made stays yours
We will not dress this up. The free plan exists so you can start with confidence, and the current limits and prices are set out clearly on our pricing page rather than guessed here. If you want the numbers, see /pricing; if you simply want the invitation out the door, start free and decide about upgrading only when a real need shows itself.
What does not change is ownership of the page. Whether you stay on the free plan for the whole event or move up halfway through, it is the same page under the same link. You keep editing it, guests keep reading it, and nothing is rebuilt when your plans grow.