Yolanda Chao, 48, of Holy Family Parish in Vancouver, British Columbia, said this was her second World Youth Day, and she will continue to come to these gatherings.
"Faith has no age," she said, laughing.
She applauded the church's initiative with young people.
"They are our new disciples," she said. "They are the new church. This is very important for us and for them. It is the youth that will carry on the word.
William Wallace, 57, of Our Lady of Good Counsel Parish in Methuen, Mass., said older pilgrims often accompany younger parishioners, but "older pilgrims may also be trying to find their way, their faith."
He said young people connect to other youths from around the world, and that benefits everyone.
"To see these kids enjoying this interaction and growing their faith provides hope," he said.
Cynthia Doss, 54, of Kuala Lumpur, Malaysia, said the warmth she feels from young people is exciting. She traveled to Brazil with her 18-year-old daughter and 20-year-old son.
"The Holy Father is so right when he stresses that we should pay attention to our youth and our elders," she said. "There is no age limit for youth. You are always as young as you feel, and age does not have an effect on our faith."
From Sao Tome and Principe off the coast of Africa, Luiza Martins Goncalvez, 48, came with a group of 46 pilgrims, many older than 35.
"We have come to join the youth," said the woman from Our Lady of Conception Parish. "We want to help them in this journey."
Many older Argentines said they made the trip to Rio to see a fellow Argentine. They said they did not come for the catechesis or the vigil.
"I have come to this because of Pope Francis. He is Argentine and I am Argentine," said Miguel Mesiti, 64. As for being surrounded by people at least 20 years younger, he said, "It is all about how old you feel inside. I feel young."