This is a topic close to my heart so forgive me if I ramble.
I come from a large family of Catholics and was born into the Catholic church myself. My family is French Catholic, Irish Catholic, Polish Catholic, and my mom's many cousins and relatives by marriage are mostly Italian Catholic. St. Louis is a really Catholic city so that's not at all unusual.
My mom was married briefly after dropping out of college and because she was married in the Catholic church she would have had to get an annulment to marry again -- but she believes in taking responsibility for your actions and acknowledging your mistakes, so saying that the awful marriage (that lasted less than a year) didn't even happen went against her personal beliefs. Instead she got a divorce. When she met my dad (also Catholic, obviously) they couldn't get married in the Catholic Church so they were married in a Lutheran church. I was still baptized and raised Catholic because both my parents believed in the fundamental tenets (mostly) and because it was such a tradition.
When it came to be time for my first Reconciliation (aka confession) and Communion, my entire class at the parish school I went to all did it together, in the spring of second grade. We spent most of the semester learning about what it meant and why we did it and all that. My parents and my extended family supported me and though I don't think I was necessarily my choice, it wasn't something unusual -- we went to Mass frequently and I went to Catholic school, after all. Well the parish priest at that time told my parents that they weren't welcome at the service when I received my Communion because they were living in sin and both my brother and I were therefore bastards.
So very shortly after that we left the Catholic church. (Sidenote: my godmother, who was also my aunt, looked into getting legal custody because my parents were leading me down the path of evil by taking me out of the Church. She didn't get it.) My parents looked around and eventually found the Episcopal (Anglican) church and realized that the fundamental similarities of belief were there but that the church as a whole was a lot more open-minded in its beliefs.
Making the transition from Catholicism to Anglicanism isn't difficult, so it sort of meshed well with the beliefs I'd already been forming. My church has confirmation at the end of 8th grade, and I went through believing as much as a 12 year old can believe, which I think is probably enough.
I still attend church, albeit less frequently because of some personal problems with the parish I grew up in. I went to Catholic grade school and high school, and I believe that, in the absence of a protestant denominational school compatible with my beliefs, Catholic school will also be my choice for my children. I have a fondness for the Catholic church but my beliefs are more in line with the Episcopal church ( as someone said, it really is Catholic light in many ways).
I believe that I can spread the Good News of the Gospels without saying 'you're wrong, be a Christian.' I have had more success in forming relationships with those of other faiths and making them more open to the concepts of Christianity by being a good Christian (well, sometimes, I'm hardly perfect) than by being a good converter. Additionally, questioning your faith and the faith of your religious leaders can often be a good way to a deeper understanding of the faith of both of you.
I also believe that structure (Catholic/religious schools, formal language in worship, rules on when you can take certain sacraments) are helpful. I have two young adopted sisters and an adopted brother. My sister, after 3 months in the U.S., who was raised pseudo-Jewish, spoke very little English, and had pretty much no idea what was going on, was led by her Sunday school teachers into taking Communion "because all the other kids in her grade are doing it." That really upset me -- I think that until you have some sort of idea what's going on (even if you can't get all of the deeper sacramental meaning of it) you have no business taking a sacrament.
But that's just me. I could be wrong.
~~Greekgrrl