[quote=Freelander]I was christened Catholic some 45 years ago. According to my sister – both of my parents are now deceased – I haven’t received First Communion or confirmation. Does this make me a non-Catholic?
Assuming it is true that you haven’t yet received First Communion or confirmation, it would make you a baptized Catholic who hasn’t completed the sacraments of initiation (baptism, First Communion, confirmation).
[quote=Freelander]What do I have to do to “return,” as it were, to the Catholic Church?
Given that siblings are a highly unreliable source of information on such matters because they are usually too young for their memories to be trusted, the first thing to do would be to contact the parish where you were baptized and ask to receive a copy of your sacramental record. If you did complete the initiatory sacraments, this will be noted in the sacramental record maintained by the parish of your baptism. If that parish no longer exists, contact the diocese in which it was located to track down where that parish’s sacramental records were sent.
If your sister is correct, then contact your local pastor for information on how to complete the sacraments. Usually, there will be a period of instruction; then you will be prepared to make your first confession. After that, you will be given First Communion and confirmed. For reasons of practicality, many parishes do this by asking such Catholics to enroll in the Rite of Christian Initiation for Adults (RCIA); but, if your pastor is amenable, you may be prepared outside of such a program.
How to Become a Catholic