Sacraments are sign language from God. They tell us something at major changes in our lives. Some of these changes are birth, growing up, marriage, and sickness. God sends a different message each time because the changes that come into our lives are different at the time. Basically God says that he loves us, is with us, and will help us through the change, whatever it is.
Confirmation is a sacrament of growing up.
When we are born, we live in a very small world. That world consists of our parents and brothers or sisters. We live in this sheltered world because we aren't ready yet to deal with a bigger world. In the same way we are also part of another small world, our parish church. We may not be aware of them at first, but they touch and influence our lives.