First of all, it is absolutely not a sin for a man and woman to live together chastely, which in your case would mean celibacy. The Church does not ban men and women from being roommates. The concern would be that might be knowingly placing yourselves in tempting situation.
Second, the idea that your girlfriend needs to live “on her own” to “find herself” prior to marrying you is modernist secular feminism, and is not nor has ever been at all countenanced by the Christian faith. We all bring baggage to our marriages, and sharing that is part of being married. Living on her own for a year is not going to magically make your girlfriend baggage-free. God made man and woman together and Christ told us that, if we do not or are not able to choose a live of celibacy as he did, we are to cleave to each other in marriage. There is nothing in the Church teaching, tradition, or history, biblical or otherwise, that says a young woman needs to live on her own after moving out of her father’s home and into the home of her husband.
NFP: Humana Vitae is explicitly clear that the legitimate purpose of NFP is to address concerns exactly like yours.
My advice is: don’t hold off proposing. However, recognize that betrothal does not have to be followed by marriage right away. Furthermore, while you are not forbidden from being roommates, you need to be very honest with yourselves about such a potential situation.
In your post, there are several signs of obfuscation. For example you say you have not really discussed your faith with her. Yet you surround this with assumptions that the only barrier to her conversion is her family Very doubtful; if she is as ignorant of the Church and the faith as you say, the process of discovery is going to be life-changing.
Furthermore you explain away her family’s behavior as “psychotic”. Unlikely, unless they have all been medically diagnosed and are off their meds. The truth, isn’t it, is that you disagree with their attitude towards you and your relationship. This doesn’t make them “psychotic”. I do not mean to say that you are lying; however, if you are absolutely convinced that you are right and they are 100% wrong, I can pretty much guarantee you that you are are wrong (which doesn’t make them right.)
In any event if you think you are going to be able to ignore the wishes of your in-laws by simply labeling them “psychotic” in your own mind, then son, you ain’t ready for marriage. You need to accept responsibility for making decisions that are against the wishes of her family, and you need to accept that they have a legitimate right and Christian obligation to express their point of view regarding your relationship.
Those two instances of obfuscation in your post cause me to believe that you may also not be being honest with yourself about how being “roommates” with your girlfriend is going to work out. Again I am not calling you a liar: we all frequently find ourselves rationalizing behavior in which we want to engage but possibly should not. Those, like you and I, who are most interested in theological study are by far the most at risk for this kind of temptation.
Finally, you need to completely divorce your girlfriend’s potential conversion from your plans to marry her. You are doing her a grave disservice by not discussing your faith with her because it happens to be inconvenient for you to do so. Presumably you think you are in love with her. Yet you are deliberately withholding from her knowledge that might help her to find to eternal life in Christ. Can you sincerely withhold this from her one day longer because it is inconvenient in the context of your relationship - and claim that you truly love her? If so, you clearly ain’t ready for marriage.
Finally, some non-spiritual advice. Putting each other through college sounds like a great way to avoid going into unnecessary debt; good idea and good for you. However, if one of you can work and support the both of you in this economy, ask yourselves why you feel the need to go to college at all. I’m not saying don’t go to college: university is a requirement for many careers. However, there are quite a lot of things you can do that are honorable, important and fulfilling (and monetarily enriching) work that do not require a college degree. Going to college doesn’t make you any smarter or more knowledgeable; you can read books and attend seminars and even write articles or papers or books all without being a “student”. If you have a career plan that requires college, go - but don’t go to college just because it’s the thing the secular media society tells you you ought to do. It is very likely that, if you work in a trade for 4 years to put your (future) wife through school, it will not make economic sense for you to quit your career and go to college. Again, it may be that you will want to switch careers and don’t mind the monetary opportunity cost; however by that time you may well be trying to conceive or already have a baby around the house and your responsibilities as a parent may preclude you from going to back to school at that time. And there is absolutely nothing wrong with that. If, on the other hand, your wife works to put you through school, keep in mind that if after that the plan is for her to go to college, it is going to be pretty much impossible for you to plan to conceive while she is busy with coursework and prior to that when she is your sole source of income and you are in school it is going to be very difficult to handle raising an infant, so you are talking about putting off first conception for from 6 to 10 years depending on how long you both take to go through all your coursework. These are all costs of going to college in addition to the monetary cost of tuition. Be sure you know what all the costs are and that you are willing to “pay” them.
Deus Tecum,
