So…am i to believe that the individual has no say in his or her status. I choose not to be Catholic. Therefore I am not Catholic. Not so?
The rest of us in your shoes also see what we consider to be an absurdity in that. Basically what the Church holds is that once you’re baptized, you’re in for eternity. You don’t ever have had to made an informed conscious choice to join, or believe in anything the Church believes. They gotcha, so they say. Now this has obvious political and economic advantages for the Church, but I also believe it has it’s downsides in the form of cafeteria Catholicism, Catholic in Name Only etc.
That said, you can assert your departure from the church on Earth through the defection process. Basically you send a letter to the canonical services person in your diocese and make a definitive statement that you have effectively left through apostasy and that you’re making the choice freely, understand the consequences etc. Within a couple of weeks, they make that notation on your baptism record and send you a polite form letter indicating it has been done. I did this in Chicago a little over a year ago.
The latest Motu Proprio has thrown it all into some confusion. I hear that in Ireland, where the process became rather popular, the bishops are putting defections on hold because of confusion over whether the latest change truly does away with defection or merely removes the one obvious canonical consequence of it. Ultimately, defection is done in your mind and heart and you can’t get too hung up on what degree of official recognition they choose to give it. I figured I did my part in good faith. I let them know where I stood and that they no longer speak in my name, and conversely, that I would not carry on as a heretic passing myself off as a Catholic.
The age question is an interesting one. Age 18 is probably a reasonable assumption, but I don’t know. My gut would be to suggest that whatever age is set for confirmation these days ought to serve as well for defection. If confirmation is really supposed to involve adult(ish) reasoning and informed choice, you ought to be able to opt out as well as in.
Bear in mind that I do not advise anyone either way on the issue. It’s a matter of one’s personal conscience.