Van Gennep's three-phase structure describes a shape rites tend to share; it says nothing about how formally, or how young, a particular body chooses to mark it, and the variation between traditions on that point is considerable.
The Jewish bar mitzvah, and its now widespread counterpart the bat mitzvah for girls, mark a fixed age of religious majority, thirteen for boys and traditionally twelve for girls, with a public reading from the Torah as the incorporation rite; the bat mitzvah's general adoption is a twentieth-century development, its first documented American instance usually dated to 1922. Christian confirmation performs a comparable function of admitting a baptised person to full participation, but denominations disagree sharply on both its age and its necessity: Catholic and Orthodox practice ties it closely to baptism and, in Orthodoxy, administers it in infancy, while many Protestant traditions treat it as an adolescent rite of personal affirmation or dispense with it altogether. The quinceanera, marking a Latin American girl's fifteenth birthday with a Mass and a celebration, developed as a blend of Catholic liturgy and regional custom rather than as a rite the church itself designed.
Secular society has not abandoned the underlying need so much as relocated it. Humanist naming ceremonies, secular coming-of-age events, and even graduation and retirement ceremonies reproduce van Gennep's separation, transition and incorporation structure with no religious content at all, which is usually taken as evidence for how deep the structure runs rather than for how essential religion is to supplying it.