My mom wants me to do a Confirmation as well. She's not very pressuring about it, but she doesn't seem to understand that my beliefs are not a simple phase.
But besides, even if you do undergo all the rituals of the Catholic church, it doesn't really matter if you decide you are not Catholic anymore. It's just fancy superstitious rituals, and it's not hard to explain that the Catholic church is just throwing stubborn tantrums if you can't remove yourself from some list.
Well, the Catholic church's fancy mathematics was part of the reason we have Protestants: People who hated the church but still kept its superstitions.