Confirmation is the sacrament of initiation that competes our Baptism.
There are three sacraments of initiation here is the correct order of these sacraments as are received through RCIA or in diocese of restored order:
In Baptism we are claimed as sons and daughters of God, we die to original sin and are born to new life in Him, and we are challenged to proclaim the gospel in word and in deed.
Confirmation equips us with what we need to complete that challenge given to us in baptism.
In the Eucharist we finally complete our initation into the Catholic Church by comming into full Communion with the Church and making a public declaration (Amen) of an inward belief that Christ is fully present in the Eucharist: body, blood, soul, and divinity.
Why do we do them out of order?
Because the Bishop is the normal person who offers this sacrament, the church started moving the age of Confirmation around the year 1300 to enable a longer period of catechesis and to address some logistical challenges the Bishop faced in gathering together all of those who needed baptism. Eucharist, however, is available at the age of reason (7 years old or so) and any priest can offer that sacrament so logistically we didn't have to wait for a bishop to visit for the faithful to receive.
So, Confirmation is not so much about choosing God, but about God strengthening us to face what lies ahead.
We generally prepare young people to be competent, independent adults through academia and extra curricular activities and rightly so, these are extremely valuable in shaping a person to participate in the world. However, there are myriad moments in life that can not be prepared for in the classroom, the sports field, or the concert hall.
- Choosing a college, a job offer, a proposal for marriage: there are decisions in life that will indefinitely impact the trajectory of our lives and no one can make these decisions for us.
- Death, illness, loss, pain, suffering: there is no handbook, no script for how to deal with these most painful parts of life.
- A spouse, children, friends, enemies: it can be extremely hard to love when love is a choice and not an emotion.
- Sharing the love of God with a world that increasingly finds God irrelevant: Christianity is anything but comfortable and easy.