I am in the same situation as the young lady, who is 23 years old. I have been with my boyfriend for almost ten years, and we need help. We keep sinning. We want to stop, but we eventually come back to our sinful ways. Since the Bible say let them be married so they won't keep sinning, we decided we will get married, even though my boyfriend thinks we should just stop because marriage is not the answer since we are both pursuing graduate studies and have no money. I say just as Paul said let them marry to keep from fornicating, but we have no money. I'm going to school and he is about to enter school. We've been dating for a long time. We are both Christians, but our fornication is hindering our walk with Christ.
The idea that a Christian can knowingly remain in sin and consider themselves to be faithful is foreign to the Scriptures. "What shall we say then? Shall we continue in sin that grace may abound? Certainly not! How shall we who died to sin live any longer in it?" (Romans 6:1-2). It is not that Christians don't sin. We are vulnerable to Satan's attacks, but a Christian doesn't accept sin in his life. See: Mission Possible: Holiness.
Even though you know you are in sin, you've accepted it and live with it. "Do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived. Neither fornicators, nor idolaters, nor adulterers, nor homosexuals, nor sodomites, nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners will inherit the kingdom of God" (I Corinthians 6:9-10).
A question I usually ask people who claim they cannot marry is: "What will change once you do marry?" In other words, I assume you two basically live together, so financially you are already attacking the costs of maintaining a home together. If you are living separately, then the combined living quarters will reduce your total costs by nearly half.
If it is the wedding itself that stops you, the answer is that it costs very little to get married. What costs so much is the fancy weddings people insist on having. A marriage at the courthouse generally costs less than $100. I've done weddings where the groom and bride spent practically nothing -- including one in the town park where everyone wore blue jeans. I think the total outlay for that one was $25 for the license. You can really show imagination when you start planning a wedding on a zero budget.
The truth is: the only thing stopping you is you.
We do not live together and have no means of paying rent. We both live with our parents and are pursuing school. My boyfriend said he wants us to live together, but we cannot afford rent and have very few money between us.
Then you should talk to your parents and figure out which would allow you to live at their house while you finish off your degrees and get on your feet financially.