Sorry to be That Person, but there's a few things wrong with this story. Mormons don't hand out pictures that look like that. Mormon missionaries travel in pairs, NEVER alone. So your "nice Mormon lady" is more likely a Jehovah's Witness.
Remember when this was the biggest problem you encountered all day? But we figured it out. Walked to the side pulled the swing away from the puddle and jumped on it. Getting off with dry feet was the next problem. But we didn't care.